Concept:The correct word must act as the object of the verb “forgot” and express the missing content of the police statement.
Explanation:The sentence says the accused forgot something.
The blank needs a noun clause that answers “what was forgotten?”
Option A, “what the police said,” gives the actual content or message spoken by the police.
Option B, “that the police said,” is incomplete because it does not state what was said.
Options C and D change the meaning by introducing time or reason, which are not suggested by the sentence.
Therefore, the most natural and grammatically correct completion is “what the police said.”
Answer:A. what the police said