identify the bias

Question

student surveys that students in his calculus class and finds that 7/33 students are physics majors. he uses the data to predict the percentage of all students at his college who are physics student

a. sampling bias because the sampling technique favors one group of individuals over another
b. response bias because individuals identified to be in the sample could not be found
c. sampling bias because individuals refused to be part of the study
d. response bias because individuals refused to be part of the study
e. non responsive bias because individuals identified to be in sample could not be found
f. non responsive because the surveyed peoples answer may not match with what they really think.

Answer 1

i think its a, b

Answer 2

There's only one right answer.

Answer 3

it says select all that apply

Answer 4

OK. You're right -- a and b