A nurse is assessing a client who has a recent diagnosis of dissociative identity disorder. The client tells the nurse, 'I think my blackouts are actually caused by low blood sugar.' The nurse should recognize the client is using which of the following defense mechanisms?

The correct answer is D: Rationalization. The client is attributing their blackouts to a seemingly logical and acceptable cause (low blood sugar) rather than acknowledging the true underlying issue of dissociative identity disorder. Rationalization involves creating logical explanations or justifications for behaviors, thoughts, or feelings that are otherwise unacceptable. In this case, the client is using rationalization to avoid facing the uncomfortable reality of their dissociative symptoms.

Incorrect choices:
A: Suppression involves consciously avoiding or pushing away thoughts or feelings. This does not apply to the client's situation.
B: Sublimation involves channeling unacceptable impulses into more socially acceptable behaviors. This is not demonstrated in the client's statement.
C: Projection involves attributing one's own thoughts or feelings to others. This is not evident in the client's statement.

Therefore, rationalization is the most appropriate defense mechanism being used by the client in this scenario.