Problem: How does the sentence end?

Samantha gave Mary vocal lessons for the upcoming school concert because 
OPTIONS:
- Samantha had well-trained vocals.
- Mary had well-trained vocals.
Answer: Samantha had well-trained vocals.

Problem: How does the sentence end?

Ian ate a lot of turkey breast but not Kevin because 
OPTIONS:
- Ian was on a vegetarian diet.
- Kevin was on a vegetarian diet.
Answer: Kevin was on a vegetarian diet.

Problem: How does the sentence end?

The doctor was able to cure Natalie and not Cynthia as 
OPTIONS:
- Natalie had early signs of her disease.
- Cynthia had early signs of her disease.
Answer: Natalie had early signs of her disease.

Problem: How does the sentence end?

When the first came around Sarah paid Rachel rent money because 
OPTIONS:
- Sarah was the owner of the property.
- Rachel was the owner of the property.
Answer:
Rachel was the owner of the property.