Problem: How does the sentence end?

Lindsey wanted to know Carrie's process, so 
OPTIONS:
- Lindsey spent a lot of time teaching them.
- Carrie spent a lot of time teaching them.
Answer: Carrie spent a lot of time teaching them.

Problem: How does the sentence end?

The piano at the bar was played more often than the harp, since 
OPTIONS:
- piano was a very uncommon instrument to learn at school.
- harp was a very uncommon instrument to learn at school.
Answer: harp was a very uncommon instrument to learn at school.

Problem: How does the sentence end?

Megan planned to pass her pencil over to Natalie shortly, as 
OPTIONS:
- Megan was just about to start her writing.
- Natalie was just about to start her writing.
Answer: Natalie was just about to start her writing.

Problem: How does the sentence end?

James needed another plate that can contain the cake when carrying it because the 
OPTIONS:
- cake is big.
- plate is big.
Answer:
cake is big.