The correct answer is B) amused.
Explanation:
* 'Amusing' describes something that causes amusement (something that is funny or entertaining).
* 'Amused' describes how someone feels when they find something funny or entertaining.
In this sentence, 'the show' caused the feeling of amusement, so the show itself was 'amusing'. The people watching the show *felt* 'amused'. However, the sentence is asking for an adjective to describe the show.
Therefore, the complete sentence is: The show was amused and we didn't want to leave. The show was so good that the audience became amused so much so that they didn't want to leave. If the sentence read "The audience was ... and we didn't want to leave" then the correct answer would be A amusing.