Problem: How does the sentence end?

Billy was preparing the mixture in the kitchen and added vinegar but not oil because the 
OPTIONS:
- vinegar was plentiful.
- oil was plentiful.
Answer: vinegar was plentiful.

Problem: How does the sentence end?

Neil identified the condition on Christopher and gave them a prescription, since 
OPTIONS:
- Neil was their patient.
- Christopher was their patient.
Answer: Christopher was their patient.

Problem: How does the sentence end?

The doctor sent Maria but not Sarah to the pharmacy because 
OPTIONS:
- Maria was very healthy.
- Sarah was very healthy.
Answer: Sarah was very healthy.

Problem: How does the sentence end?

The powerful fragrance of the lemon lavender scented candle was excessive to Christine but acceptable to Jessica because 
OPTIONS:
- Christine had a highly acute sense of smell.
- Jessica had a highly acute sense of smell.
Answer:
Christine had a highly acute sense of smell.