[Q]: How does the sentence end?

Christopher admired the beard that Nick had grown, so 
OPTIONS:
- Christopher asked how he did it.
- Nick asked how he did it.

[A]: Christopher asked how he did it.
QUES: Continue writing.

When Erin locked her keys in the car she called Megan for help. 

OPTIONS:
- Erin had spare keys.
- Megan had spare keys.
+++++++++
ANS: Megan had spare keys.
Problem: How does the sentence end?

In the garden, Betty is having more success with growing flowers than Kayla due to 
OPTIONS:
- Betty using a weak fertilizer.
- Kayla using a weak fertilizer.
Answer: Kayla using a weak fertilizer.
sentence: Derrick used nail polish to paint their nails red while Ryan didn't use any at all, so  OPTIONS:
- Derrick had colorful fingernails.
- Ryan had colorful fingernails.
complete: Derrick had colorful fingernails.
Justin was so clingy with her new boyfriend Nelson, that 
OPTIONS:
- Justin began to suffocate him with attention.
- Nelson began to suffocate him with attention.
Justin began to suffocate him with attention.
Problem: Continue the following story.

Since Elena fell into the river while Rebecca remained in the boat, 
OPTIONS:
- Elena remained dry on the excursion.
- Rebecca remained dry on the excursion.
Here's how I want to continue it:
Rebecca remained dry on the excursion.