Sentence 3, i think. because if her sister answers her phone than jayla will figure out if something is wrong
The predicate adj. would be " good ". It is modifying the subject " idea ".
I'd say it was D or the last choice. It makes most sense to me.
Answer:
In a beat-up old trunk, in my grandmother's attic, we found old letters, a diary,
postcards, and a soldier's uniform, from the Civil War.