The workers in a factory currently earn $240 for a 40 hour week. The management offers them a choice between either a 10 perent wage incresase in the weekly wage to $260 along with a reduction time from 40 to 36 hours. Disregarding the value of leisure time, what is the oppurtunity cost to each worker of opting for the 39 hour week.

a) $6

b) $24

c)$20

d) $4