Susan is a teacher and owns a small rural home with a $150,000 15-year mortgage. She is considering going to graduate school, which will mean taking out another loan. What might be her first step to determine whether this is financially feasible? 

 a) Get a second job

b) Take out a balloon mortgage

c) Delay going to graduate school until the loan is paid off 

d) Investigate refinancing for a 30-year mortgage