During the summer you have made the decision to attend summer school, which
precludes you from working at your usual summer job in which you normally earn $6,000 for the
summer. Your tuition cost is $3,000, books and supplies cost $300, and room and board cost
$1,000. The opportunity cost of attending summer school is

A) $10,300.
B) $6,000.
C) $4,300.
D) $3,300.