Problem: How does the sentence end?

Katrina was comfortable presenting the group project, but Sarah blanched at the idea because 
OPTIONS:
- Katrina had experience speaking in public.
- Sarah had experience speaking in public.
Answer: Katrina had experience speaking in public.

Problem: How does the sentence end?

Rebecca wiped her glasses with a rag and then switched to a tissue, because the 
OPTIONS:
- rag would get the job done.
- tissue would get the job done.
Answer: tissue would get the job done.

Problem: How does the sentence end?

The beam could no longer support the roof, as the 
OPTIONS:
- beam was too weak for it.
- roof was too weak for it.
Answer: beam was too weak for it.

Problem: How does the sentence end?

Rebecca taught Samantha about mushroom picking because 
OPTIONS:
- Rebecca was ignorant about which ones were edible.
- Samantha was ignorant about which ones were edible.
Answer:
Samantha was ignorant about which ones were edible.