Which word correctly completes the sentence: "The PTA held ___ annual fundraiser."

The correct word that completes the sentence is "its." This choice is appropriate because "its" is a possessive pronoun used to indicate that something belongs to or is associated with a non-human subject, in this case, the PTA (Parent-Teacher Association).

In this context, the PTA is an organization, and the fundraiser is something that belongs to or is hosted by the PTA, making "its" the correct choice.

The other options do not fit the context of the sentence. "There" refers to a place and does not show possession. "Their" is a possessive pronoun that refers to a group of people, but in this scenario, it would incorrectly suggest that the fundraiser belongs to multiple subjects rather than specifically to the PTA. "It's" is a contraction of "it is" or "it has," which also does not convey possession and would not make sense in the sentence.