The Varying Levels of Support for the Iraq War Highlight

The varying levels of support for the Iraq War highlight what aspect of public opinion?

A) Answers may be affected by even ostensibly minor changes in question wording.
B) Even though most Americans lacked specific knowledge, they were willing to express their opinions.
C) The margin of error meant that it was very difficult to ascertain the true feelings of the American people on the question.
D) The public was more supportive of the war in larger samples than smaller samples, and this is a common concern.