Problem: How does the sentence end?

The plug that I bought from the hardware store didn't fit the drain because the 
OPTIONS:
- plug was too fat.
- drain was too fat.
Answer: plug was too fat.

Problem: How does the sentence end?

Eric was having a hard time sleeping at night while Christopher slept well because 
OPTIONS:
- Eric had a guilty conscience.
- Christopher had a guilty conscience.
Answer: Eric had a guilty conscience.

Problem: How does the sentence end?

I filled the cups with strawberries but it wasn't large enough.  The 
OPTIONS:
- strawberries were too small.
- cups were too small.
Answer: cups were too small.

Problem: How does the sentence end?

The ax split the wood in just one hit and it is amazing because the 
OPTIONS:
- ax is strong.
- wood is strong.
Answer:
ax is strong.