Which sentence contains an antecedent that is unclear, missing, or confusing?


A.

If you want to go to garage sales with Rachel on Saturday, she leaves at 7 a.m.


B.

During the announcements this morning, they said that football practice was canceled.


C.

My sister and I have been taking cooking classes, but she's a much better chef than I am.


D.

In the note left on the counter, my mother said she wouldn't be home until later.