[Q]: How does the sentence end?

I picked up my blue cup that was by the sink while I was doing the dishes but there was nothing in it. The 
OPTIONS:
- cup was empty.
- sink was empty.

[A]: cup was empty.
QUES: Continue writing.

Derrick is flexible enough to do the splits, and Robert is not, so 

OPTIONS:
- Derrick likely rarely stretches.
- Robert likely rarely stretches.
+++++++++
ANS: Robert likely rarely stretches.
Problem: How does the sentence end?

She put mustard on the sandwiches, but not on the fries, because she thought the 
OPTIONS:
- sandwiches had been served tasty.
- fries had been served tasty.
Answer: fries had been served tasty.
sentence: Kayla had less wrinkles than Samantha because  OPTIONS:
- Kayla did take care of her skin and didn't have a facelift.
- Samantha did take care of her skin and didn't have a facelift.
complete: Samantha did take care of her skin and didn't have a facelift.
Christopher found it easier to work with the children than Randy because 
OPTIONS:
- Christopher had previous teaching experience.
- Randy had previous teaching experience.
Christopher had previous teaching experience.
Problem: Continue the following story.

Ian wanted to treat Brian's agoraphobia because 
OPTIONS:
- Ian is a doctor and wants him to get better.
- Brian is a doctor and wants him to get better.
Here's how I want to continue it:
Ian is a doctor and wants him to get better.