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.