Problem: How does the sentence end?

Measles was going around and Steven was afraid they'd catch it but Nelson was not, because 
OPTIONS:
- Steven had been vaccinated and were immune.
- Nelson had been vaccinated and were immune.
Answer: Nelson had been vaccinated and were immune.

Problem: How does the sentence end?

While baking cookies, Carrie was asked by Emily to buy more chocolate chips after they ran out. 
OPTIONS:
- Carrie drove to the store and brought some back.
- Emily drove to the store and brought some back.
Answer: Carrie drove to the store and brought some back.

Problem: How does the sentence end?

Adoption was something Jessica wanted to do but Kayla didn't, so 
OPTIONS:
- Jessica cares less for kids.
- Kayla cares less for kids.
Answer: Kayla cares less for kids.

Problem: How does the sentence end?

Elena bought a new dishwasher with 10 years old warranty and showed off to Christine, 
OPTIONS:
- Elena was so proud.
- Christine was so proud.
Answer:
Elena was so proud.