A Radio Talk Show Invites Listeners to Call a Telephone

A radio talk show invites listeners to call a telephone number to vote Yes or No on whether they support a bond issue for a new school. About 1500 people call in. Over 80 percent say No. As an estimate of community opinion, this result is:

A) accurate to within ± 3 percent with 95 percent confidence.
B) not trustworthy because of nonsampling errors.
C) not valid because the sample size of 1500 is too small.
D) unethical due to lack of informed consent.
E) badly biased due to voluntary response.