Determine whether the following sample may be biased and explain.

john chooses 100 students from a list of students enrolled at his school and surveys these students about their favorite hobby.

a.) the sample may be biased because students have different hobbies.

b.) the sample may be biased because some students do not have a hobby.

c.) the sample is not biased because it is a random sample.

d.) the sample may be biased because the sample is from the incorrect population.