Read the text and determine if the sentence is true (see options at the end):

Cerastium is a genus of annual, winter annual, or perennial plants belonging to the family Caryophyllaceae. They are commonly called mouse-ear chickweed. Species are found nearly worldwide but the greatest concentration is in the northern temperate regions. There are about 200 species. A number are common weeds in fields and on disturbed ground.

Sentence: Cerastium are the only type of Caryophyllaceae.
Choices: (a). Yes. (b). It's impossible to say. (c). No.
(b).