Problem: How does the sentence end?

Jennifer bought a video game at the mall while Christine bought a book, and when they got home 
OPTIONS:
- Jennifer began playing what they bought.
- Christine began playing what they bought.
Answer: Jennifer began playing what they bought.
sentence: When picking exercise, both the treadmill and weight bench are good for you although when using the  OPTIONS:
- treadmill your heart will beat faster.
- weight bench your heart will beat faster.
complete: treadmill your heart will beat faster.
She put the plush rug rather than the rattan rug in her living room because the 
OPTIONS:
- plush rug was meant for indoors.
- rattan rug was meant for indoors.
plush rug was meant for indoors.
Input: Continue writing.

While they ate dinner, Emily asked Erin for advice on getting over a heartbreak, because 
OPTIONS:
- Emily was new to matters of romance and love.
- Erin was new to matters of romance and love.

Continued: Emily was new to matters of romance and love.
Story needs to be completed:
Jessica applied the serum carefully with a small brush before going over it with a roller, because the 
OPTIONS:
- roller always had to be used second.
- brush always had to be used second.

My choice:
roller always had to be used second.
Problem: How does the sentence end?

Joseph gave Ryan some of his cereal as 
OPTIONS:
- Joseph forgot to bring his breakfast to school.
- Ryan forgot to bring his breakfast to school.
Answer:
Ryan forgot to bring his breakfast to school.