Which of the following is an exception to hearsay that does not require the declarant to be unavailable?

The exception to hearsay that does not require the declarant to be unavailable is the present state of mind. This exception allows a party to introduce statements made by a declarant about their own mental state, emotions, or feelings at the time the statement was made. Such statements are relevant because they can provide context for the declarant's actions and intentions, helping to establish the truth of the matter being asserted without the need for the declarant’s presence in court.

In contrast, character evidence, general reputation, and prior convictions may not fit within the same exception framework as present state of mind. Character evidence typically involves the traits or characteristics of a person and often requires the setup of the character as an issue in the case, which might not directly lead to an exception to hearsay. General reputation for certain types of knowledge requires proof of that reputation but does not independently allow for hearsay without the declarant being unavailable. Prior convictions also have their own rules of admissibility and do not directly reference an exception based on the declarant's mental state, therefore necessitating additional layers of legal consideration.