Problem: How does the sentence end?

Elena was slimmer than Mary, so 
OPTIONS:
- Elena started to worry about going on a diet and her weight.
- Mary started to worry about going on a diet and her weight.
Answer: Mary started to worry about going on a diet and her weight.
sentence: Donald wasn't as diligent as Kevin when guarding the gate, so  OPTIONS:
- Donald was punished by the sergeant.
- Kevin was punished by the sergeant.
complete: Donald was punished by the sergeant.
Patricia tried to disarm the robber while Monica called the police. 
OPTIONS:
- Patricia had always been bold when confronted.
- Monica had always been bold when confronted.
Patricia had always been bold when confronted.
Input: Continue writing.

Bob went to the vehicle dealer to trade his truck for a motorcycle, because the 
OPTIONS:
- truck was new.
- motorcycle was new.

Continued: motorcycle was new.
Story needs to be completed:
In college, Brett needed a tutor for calculus while Kevin did not because 
OPTIONS:
- Brett was challenged by the material.
- Kevin was challenged by the material.

My choice:
Brett was challenged by the material.
Problem: How does the sentence end?

Chris started using the night light instead of leaving the bathroom light on, because the 
OPTIONS:
- night light used more electricity.
- bathroom light used more electricity.
Answer:
bathroom light used more electricity.