Answer:
factory overhead efficiency variance = $90
so correct option is $90 unfavorable
Step-by-step explanation:
given data
overhead rate = $3.75 per direct labor hour
90% capacity = 900 standard direct labor hour
80% capacity = 800 standard
factory overhead 80% capacity = $3,150
fixed overhead = $1,350
actual factory overhead cost = $3,800
fixed factory overhead = $1300
to find out
variable factory overhead efficiency variance
solution
we know that variance is difference between the actual costs and the budgeted cost
now we get here standard variable overhead rate at 80% capacity that is express as
Standard variable overhead rate = ( Budgeted factory overhead - Fixed overhead ) ÷ Direct labor hours .......................1
put here value we get
Standard variable overhead rate =

Standard variable overhead rate = $2.25
and
now we get here factory overhead efficiency variance that is express as
factory overhead efficiency variance = Standard variable overhead rate × (actual direct labor hours - Budgeted direct labor hours ) ...................2
put here value we get
factory overhead efficiency variance = $2.25 × ( 840 - 800 )
factory overhead efficiency variance = $90
and actual cost is greater than the budgeted cost
so correct option is $90 unfavorable