Answer:
the exuberant crowd
Step-by-step explanation:
Antecedent is a noun which is replaced by a pronoun in order to avoid repetition.
Here's an example to make things more clear:
Mary lost her keys, but she later found them under the table.
So, the pronoun "them" replaces the noun "keys" which means that the noun "keys" is an antecedent.
Following this logic, we will conclude that the antecedent for the pronoun "their" is "the exuberant crowd".