Problem: How does the sentence end?

My cousin decided to use the pot and not the pan because the 
OPTIONS:
- pot was shallow.
- pan was shallow.
Answer: pan was shallow.
sentence: The husband liked living in an urban area more than a suburban area. The  OPTIONS:
- urban was more boring.
- suburban was more boring.
complete: suburban was more boring.
The cook tried to put the bagels in the cases but the 
OPTIONS:
- cases were too small.
- bagels were too small.
cases were too small.
Input: Continue writing.

Angela was put at ease by Elena during the tense situation, since 
OPTIONS:
- Angela tended to be calm.
- Elena tended to be calm.

Continued: Elena tended to be calm.
Story needs to be completed:
The bake sale was underway and no one was buying the vegan cookies but everyone loved the fudge brownies because the 
OPTIONS:
- cookies were plain.
- brownies were plain.

My choice:
cookies were plain.
Problem: How does the sentence end?

Jim threw out the book and read a letter instead because the 
OPTIONS:
- letter was too short.
- book was too short.
Answer:
book was too short.