Question ID:PT80 S3 Q21 Passage:Three real estate companies‚ RealProp, Southco, and Trustcorp‚ are considering trading buildings with one another. Each building they own is categorized as either class 1, class 2, or class 3, depending on its approximate value:RealProp owns the Garza Tower (class 1), the Yates House (class 3), and the Zimmer House (class 3). Southco owns the Flores Tower (class 1) and the Lynch Building (class 2). Trustcorp owns the King Building, the Meyer Building, and the Ortiz Building, all of which are class 2.Each trade must be of exactly one of the following three kinds:Trading one building for one other building of the same classTrading one class 1 building for two class 2 buildingsTrading one class 2 building for two class 3 buildings Stem:If RealProp owns only class 2 buildings after some number of trades, which one of the following must be true? Correct Answer Choice:AChoice A:Trustcorp owns a class 1 building. Choice B:Trustcorp owns the Meyer Building. Choice C:Southco owns a class 2 Building. Choice D:Southco owns both of the class 3 buildings. Choice E:Southco owns the Flores Tower.