Stacy has a difficult time answering the question "Should parents increase the likelihood of desirable behaviors in their children by using reinforcement and punishment?" because it is a(n) question.

double-barreled question

Explanation:

A double-barreled question is a question that comprises two or more topics or issues , but is expected to have just one answer. A double barreled question is sometimes referred to as an informal fallacy. It also be called a double-direct question or compound question. It is usually advisable to avoid such questions in  survey, but can be used in court during cross examination or other researches.

For example the question above touches on two separate issues: the use of reinforcement and the use of punishment at the same time, by parents, as a means to increase the likelihood of desirable behaviors in their children. Stacy found it difficult to answer this question because it is a double-barreled question.