The correct answer is: "The audience was ready for the game to begin."
In this sentence, "audience" is a collective noun that refers to a group of individuals. Although the sentence states "was" which is singular, the noun itself is plural in the sense that it refers to multiple people.
However, if you are looking for a sentence that directly uses a plural collective noun, none of the provided sentences fit that description perfectly, as they all use singular verbs with their respective collective nouns.
If you're seeking a sentence that uses "team" or "choir," it's important to note that these terms are also collective nouns referring to groups, but they do not indicate a plural form even when they mean more than one person. The last sentence, "The visiting team were putting on their uniforms," incorrectly uses "were" instead of "was," making it an example of an informal usage but not a plural collective noun.
To clarify, none of the sentences technically contain a plural collective noun that is standard in grammatical terms, but "audience," "team," and "choir" all refer to groups. Therefore, the best option in terms of collective nouns still refers to the first sentence.