Problem: How does the sentence end?

Angela received advice about a good diet for a dog from Felicia because 
OPTIONS:
- Angela was a vet.
- Felicia was a vet.
Answer: Felicia was a vet.
sentence: Elena had a lot of fear of heights while Cynthia was fearless, and  OPTIONS:
- Elena wanted to go skydiving.
- Cynthia wanted to go skydiving.
complete: Cynthia wanted to go skydiving.
Lawrence refused to speak in front of the class even after being encouraged by Nelson, because 
OPTIONS:
- Lawrence wasn't convincing enough.
- Nelson wasn't convincing enough.
Nelson wasn't convincing enough.
Input: Continue writing.

Megan has a smaller body than Mary because 
OPTIONS:
- Megan lifts weights every other day at the gym.
- Mary lifts weights every other day at the gym.

Continued: Mary lifts weights every other day at the gym.
Story needs to be completed:
Samantha really enjoyed feeding hungry people, Angela did not therefore 
OPTIONS:
- Samantha decided to become a chef.
- Angela decided to become a chef.

My choice:
Samantha decided to become a chef.
Problem: How does the sentence end?

They replaced the old futon with a memory foam mattress because the 
OPTIONS:
- futon had a high level of comfort.
- mattress had a high level of comfort.
Answer:
mattress had a high level of comfort.