Final answer:
The complement of Mariah choosing three mystery novels would be choosing no mystery novels.
Step-by-step explanation:
The complement of an event refers to all the outcomes that are not included in that event. In this case, the event is Mariah choosing three mystery novels. By definition, the complement of Mariah choosing three mystery novels would be Mariah not choosing three mystery novels. This means that the complement includes all other possible combinations of novels that Mariah could choose.
A) Choosing three adventure novels: This is an example of a possible outcome in the complement.
B, C, and D) Choosing one, two, or no mystery novels: These are also examples of possible outcomes in the complement.
So, the correct option for the complement of Mariah choosing three mystery novels would be Option D) Choosing no mystery novels.