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.