Problem: How does the sentence end?

The place that I live is quieter than the area that my mom lives, because the 
OPTIONS:
- place is in the countryside.
- area is in the countryside.
Answer: place is in the countryside.
sentence: Bill got a new king sized mattress but had to throw out his old queen bed frame because the  OPTIONS:
- mattress was larger.
- bed frame was larger.
complete: mattress was larger.
There were more rodents in the cage than in the box because the 
OPTIONS:
- cage was more spacious.
- box was more spacious.
cage was more spacious.
Input: Continue writing.

Erin was a slow learner while Christine was a quick learner, so 
OPTIONS:
- Erin was held back a grade.
- Christine was held back a grade.

Continued: Erin was held back a grade.
Story needs to be completed:
Dennis tried to kill ants with pesticide and Jeffrey asked them not to, because 
OPTIONS:
- Dennis was unworried about being poisoned.
- Jeffrey was unworried about being poisoned.

My choice:
Dennis was unworried about being poisoned.
Problem: How does the sentence end?

The tornado demolished the house but left the barn intact, as the 
OPTIONS:
- house was a rugged structure.
- barn was a rugged structure.
Answer:
barn was a rugged structure.