Willis Corporation manufactures industrial-sized gas furnaces and uses budgeted machine-hours to allocate variable manufacturing overhead. The following information pertains to the company's manufacturing overhead data:

Budgeted output	30,000 units
Budgeted machine-hours	10,000 hours
Budgeted variable manufacturing overhead costs for 30,000 units	$322,500
Actual output produced	44,000 units
Actual machine-hours used	14,400 hours
Actual variable manufacturing overhead costs	$484,000

What is the variable overhead rate variance?

Select one:

a. $19,600 unfavourable

b. $19,600 favourable

c. $13,611 favourable

d. $13,611 unfavourable

e. $11,000 favourable