The following standards for variable manufacturing overhead have been established for a company that makes only one product:

Standard hours per unit of output	7.8 hours
Standard variable overhead rate	$12.55 per hour

The following data pertain to operations for the last month:

Actual hours	2,900 hours
Actual total variable overhead cost	$36,975
Actual output	200 units

What was the variable overhead efficiency variance for the month?

Multiple Choice

• $580 unfavourable.
• $17,397 unfavourable.
• $16,817 unfavourable.
• $0.