Carrie was a teacher of math and Elena was their student, so 
OPTIONS:
- Carrie gave lots of homework.
- Elena gave lots of homework.
Carrie gave lots of homework.

Rachel just put a new sink in the bathroom unlike Patricia because 
OPTIONS:
- Rachel was renovating the house.
- Patricia was renovating the house.
Rachel was renovating the house.

As they walked through the dark forest, Katrina could see much better than Amy, because 
OPTIONS:
- Katrina was the one carrying a flashlight.
- Amy was the one carrying a flashlight.
Katrina was the one carrying a flashlight.