Josephina is facing a decision similar to Frank’s. If she goes to college, she will spend $21,000 on tuition, $1,600 on books, and $ 7,200 on room and board. If she does not go to college, she will earn $16,000 working in a store and spend $12,000 on room and board. What is Josephina’s opportunity cost of going to college? 
 a. $33,800 
 b. $42,600 
 c. $49,800 
 d. $57,000