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 $2,000. 3. work full-time earning $4,900. what is susan's incremental profit if she chooses option 3 over option 2?