A recent General Social Survey asked subjects whether they supported legalized abortion in each of seven circumstances. The percentage who supported legalization varied between 44.6% (if the woman is not married) to 88.6% (if the woman’s health is seriously endangered by the pregnancy). This indicates that
a. Responses can depend greatly on the question wording.
b. Non experimental studies can never be trusted.
c. The sample must not have been randomly selected.
d. The sample must have had problems with response bias.