Which sentence incorrectly uses an apostrophe to show possession?

AAre you going to Mandy's party on Thursday?
BThe man who sang during half-time is Amys' dad.
CThe servant was the princess's best friend.

Verified Answer :

BThe man who sang during half-time is Amys' dad.

It should be "The man who sang during half-time is Amy's dad."

B. The man who sang during half-time is Amys' dad.
Amy is herself, meaning as it is going to be "Amy's"