Carl is considering attending a concert with a ticket price of $35. He estimates that the cost of driving to the concert and parking there will total an additional $20. In order to attend the concert, Carl will have to take time off from his part-time job or forgo studying for an exam scheduled for the next morning. He estimates that he will lose 5 hours at work, at a wage of $6 per hour, or 5 hours of study time. If Carl considers studying the best alternative use of his time, his opportunity cost of attending the concert equals
a. $55
b. $55 plus the value of the higher exam grade he could earn by studying for 5 hours
c. $85 plus the value of the higher exam grade he could earn by studying for 5 hours
d. $85 minus the value of the higher exam grade he could earn by studying for 5 hours
e. $55 minus the value of the higher exam grade he could earn by studying for 5 hours