hich of the following sentences contains an incorrect pronoun shift?

(1 point)
Betsy was so excited to get her car back from the
mechanic.
I thought I saw a dog bury their bone under the tree.
Joe's grandfather broke his favorite plate in the
dishwasher.
Avery and Jerry brought their dad a slice of cake from
dinner.

I thought I saw a dog bury their bone under the tree.