IN: Which person is they?
The graduate students spend every waking moment studying for their classes since they offer much knowledge and tests as part of their itinerary.

OPTIONS:
- The graduate students
- their classes
OUT: their classes

IN: Which person is they?
The band connected well to their fans, so they continued to buy albums.

OPTIONS:
- The band
- their fans
OUT: their fans

IN: Which person is they?
Amazon recently upstaged Gamestop on Battlefield 3 pre-orders because they lowered their price 30 percent below the competitor.

OPTIONS:
- Amazon
- Gamestop
OUT: Amazon

IN: Which person is he?
Mark tackled the quarterback, but he was penalized.

OPTIONS:
- Mark
- the quarterback
OUT:
Mark