Which of the Following Statements Concerning Sampling Bias Is NOT

Which of the following statements concerning sampling bias is NOT true?

A) Pollsters are often unaware of the problem of sampling bias.
B) The chief source of sampling bias today is nonresponse.
C) Changing patterns of telephone technology and use are part of the reason for sampling bias today.
D) Older women tend to be oversampled, whereas younger men tend to be undersampled.
E) Pollsters compensate for undersampling by the use of weighting.