In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).
Q: Context: Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology: "Niobe", daughter of "Tantalus" since it is so similar to tantalum., Stibnite, sometimes called antimonite, is a sulfide mineral with the formula SbS. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metalloid antimony. The name is from the Greek  "stibi" through the Latin "stibium" as the old name for the mineral and the element antimony., Pyrochlore (Na,Ca)NbO(OH,F) is a mineral group of the niobium end member (pyrochlore supergroup)., A metalloid is any chemical element which has properties in between those of metals and nonmetals, or that has a mixture of them. There is neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such. Despite the lack of specificity, the term remains in use in the literature of chemistry., Lead, from the Old English "léad", is a chemical element with atomic number 82 and symbol Pb (after the Latin, "plumbum"). It has the second highest atomic number of all practically stable elements. As such, lead is located at the end of some decay chains of heavier elements, which in part accounts for its relative abundance: its stability exceeds those of other similarly-numbered elements. Lead is a soft, malleable, and heavy metal. Freshly cut lead has a bluish-white color that soon tarnishes to a dull grayish color when exposed to air; as a liquid, it has a shiny chrome-silver luster. Lead's density of 11.34 g/cm exceeds those of most common materials. , A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids. The study of minerals is called mineralogy., Antimony is a chemical element with symbol Sb (from ) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (SbS). Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name, kohl. Metallic antimony was also known, but it was erroneously identified as lead upon its discovery. In the West, it was first isolated by Vannoccio Biringuccio and described in 1540., Vannoccio Biringuccio, sometimes spelt Vannocio Biringuccio (c. 1480  c. 1539), was an Italian metallurgist. He is best known for his manual on metalworking, "De la pirotechnia", published posthumously in 1540.
Biringuccio is considered by some as the father of the foundry industry as "De la pirotechnia" is the first printed account of proper foundry practice. It also gives details of mining practice, the extraction and refining of numerous metals, alloys such as brass, and compounds used in foundries and explosives. 
It preceded the printing of "De re metallica" by Georgius Agricola by 14 years., In chemistry and physics, the atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an uncharged atom, the atomic number is also equal to the number of electrons., A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei (i.e. the same atomic number, "Z"). There are 118 elements that have been identified, of which the first 94 occur naturally on Earth with the remaining 24 being synthetic elements. There are 80 elements that have at least one stable isotope and 38 that have exclusively radioactive isotopes, which decay over time into other elements. Iron is the most abundant element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust., Stibiconite is an antimony oxide mineral with formula : Sb3O6 ( OH ) . Its name originates from Greek `` stibi '' ( antimony ) and `` konis '' ( powder ) , alluding to its composition and habit . It is a member of the pyrochlore super group ., Subject: stibiconite, Relation: subclass_of, Options: (A) account (B) antimony (C) arabic (D) atom (E) brass (F) c (G) charge (H) chemical compound (I) chemical element (J) chemistry (K) definition (L) english (M) formula (N) foundry (O) greek (P) iron (Q) isotope (R) latin (S) lead (T) liquid (U) material (V) medicine (W) member (X) metalloid (Y) metallurgist (Z) mineral ([) mixture (\) mythology (]) niobium (^) nucleus (_) number (`) oxygen (a) part (b) printing (c) pyrochlore supergroup (d) second (e) space (f) species (g) study (h) supergroup (i) white
A: 
pyrochlore supergroup