Answer:
Option c is correct
 Fixed overhead cost variance  = $18,000 unfavorable
Explanation:
The fixed overhead costs variance is the difference between the absorbed overheads and actual fixed cost incurred
Absorbed fixed overhead =FOAR × actual output
FOAR - fixed overhead absorption rate = $8.00 per unit
Absorbed overhead = $8.00 per unit  × 40,000 =  $320000
Actual overhead cost                          $338,000
Fixed overhead cost variance                  $18,000 unfavourable