Susan Conducts a Telephone Survey About Offshore Drilling

Susan conducts a telephone survey about offshore drilling. The people who respond to her calls are overwhelmingly senior citizens, with very few young adults answering her survey questions. Her sample is likely to be ________.

A) biased, because younger and older voters hold different opinions on the issue
B) biased if a greater number of older voters than younger voters respond
C) biased, because she did not randomly select her respondents
D) unbiased if younger and older voters hold similar opinions on the issue
E) unbiased, because the age of a respondent does not matter