Read the sentence.

No one could believe their luck when the owner of the restaurant offered free dessert to all.

What is the agreement error in this sentence?

The pronoun “their” does not match its antecedent in number.
The pronoun “their” does not match its antecedent in person.
The pronoun “their” does not match its antecedent in case or number.
The pronoun “their” does not match its antecedent in number or person.