To estimate the mean number of text messages sent by cell-phone users, a researcher chooses a location on a college campus in the city and surveys the first 50 people who walk past. These subjects are asked how many text messages they have sent in the past 24 hours. Is it likely that bias will be present in the sample? Possible Answers:
A:Because this is a convenience sample, it is likely that the sample results will be unbiased.

B:Because this is a convenience sample of college students, it is likely that bias is present and that the results will overestimate the mean number of text messages sent.

C:Because this is a convenience sample of college students, it is likely that bias is present and that the results will underestimate the mean number of text messages sent.

D:Because this is a voluntary response sample of college students, it is likely that bias is present and that the results will overestimate the mean number of text messages sent.