Problem: Nick gets jock itch a lot, while Jason has never even worn a jock strap.

My choice: Nick is the athlete.

Problem: Erin was always trying to follow Sarah's correct grammar, because

My choice: Sarah was controlling and anal retentive.

Problem: The business of Jeffrey did better than the one of Justin because

My choice: Jeffrey did more marketing.

Problem: Emily bought a fruit tree to plant from Katrina because

My choice:
Emily had a bare orchard.