Millonzi Corporation has a standard cost system in which it applies manufacturing overhead to products on the basis of standard machine hours (MHs). The company has provided the following data for the most recent month:
| Budgeted level of activity | 3,600 | MHs |
| Actual level of activity | 3,500 | MHs |
| Standard variable manufacturing overhead rate | $6.30 | per MH |
| Actual total variable manufacturing overhead | $21,000 |
| What was the variable overhead rate variance for the month? |
| $600 unfavorable | |
| $630 favorable | |
| $1,680 favorable | |
| $1,050 favorable |