Problem: How does the sentence end?

The housesitter wrote the messages on the chalkboard instead of the notepad because the 
OPTIONS:
- chalkboard was more obvious.
- notepad was more obvious.
Answer: chalkboard was more obvious.

Problem: How does the sentence end?

Although she was mad at both, the friend felt more betrayed by Emily than Kayla because 
OPTIONS:
- Emily had kept the secret.
- Kayla had kept the secret.
Answer: Kayla had kept the secret.

Problem: How does the sentence end?

Ryan liked big dogs while Kyle thought small dogs were preferable. 
OPTIONS:
- Ryan bought a chihuahua from the breeder.
- Kyle bought a chihuahua from the breeder.
Answer: Kyle bought a chihuahua from the breeder.

Problem: How does the sentence end?

Amy drove Christine to the vacation home because 
OPTIONS:
- Amy was insecure about driving on the highway.
- Christine was insecure about driving on the highway.
Answer:
Christine was insecure about driving on the highway.