Susan is trying to decide whether or not to attend college during the next 12 week session. She has the following options:

1. Attend college full-time at a cost of $1,200
2. Attend college part-time at a cost of $500 and work part time earning $1,900
3. Work full- time earning $4,500

What is Susan's incremental profit if she chooses option 3 over option 2?