You want to know whether the students in your school enjoy the school lunch. You survey every student in your class. Is this survey biased or unbiased?

A)Unbiased because the sample only included the students in one class.
B)Biased because the sample only included the students in one class.
C)Biased because the sample included all the students in the class.
C)Unbiased because the sample included all the students in the class.