A Political Party Sends a Mail Survey to 1500 Randomly

A political party sends a mail survey to 1500 randomly selected registered voters in a community. The survey asks respondents to give an opinion about the job performance of the current president. Of the 1500 surveys sent out, 480 are returned, and of these, only 120 show that the respondent is satisfied with the president's job performance. This is an example of:

A) a survey with little bias, because an individual will know for certain whether he or she approves of the president's job performance.
B) a survey with little bias, because 1500 voters represent an important part of the president's district.
C) a survey with no bias.
D) None of the answer options is correct.