A company allocates its variable factory overhead based on direct labor hours

A company allocates its variable factory overhead based on direct labor hours. During the past three months, the actual direct labor hours and the total factory overhead allocated were as follows:

                                                               June                     July                    August

Direct labor hours                           1,000                    3,000                    5,000

Total overhead allocated              $80,000                $140,000              $200,000

Based upon this information, monthly fixed factory overhead was:

A) $30,000

B) $50,000

C) $46,667

D) $33,333