Problem: How does the sentence end?

Arnold liked receiving the note more than the letter. The 
OPTIONS:
- note was more difficult to read.
- letter was more difficult to read.
Answer: letter was more difficult to read.

Problem: How does the sentence end?

The guitar that I bought played better than the violin, because the 
OPTIONS:
- guitar was very old.
- violin was very old.
Answer: violin was very old.

Problem: How does the sentence end?

I tossed the arugula with oil and vinegar and ate it, but tossed the lettuce in the trash, because the 
OPTIONS:
- arugula was rotten.
- lettuce was rotten.
Answer: lettuce was rotten.

Problem: How does the sentence end?

Matthew told Justin the proper way for storing ginger since 
OPTIONS:
- Matthew knew they weren't doing it correctly.
- Justin knew they weren't doing it correctly.
Answer:
Matthew knew they weren't doing it correctly.