Which sentence uses parentheses incorrectly?

A
The best part of a picnic is (cooking juicy burgers) on an outdoor grill.

B
History (my best subject in school) is the first class on my schedule this year.

C
A giraffe (Jim's favorite animal) spends most of its day eating leaves from trees.

D
My uncle is an antiques dealer (a fascinating career, I think) in Atlanta, Georgia.

A

The best part of a picnic is (cooking juicy burgers) on an outdoor grill.