Before Taking This Class,a Student Visits the "Rate My Professors

Before taking this class,a student visits the "Rate my Professors" website to read comments about the professor.The student should:

A) be confident that these responses are based on a representative sample.
B) be cautious,as these responses involve a non-representative sample.
C) be confident that these responses are completely unbiased.
D) conclude that these responses are completely useless.