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

Standard hours per unit of output 5.6 hours
Standard variable overhead rate $12.00 per hour
The following data pertain to operations for the last month:

Actual hours 2,600 hours
Actual total variable overhead cost $31,330
Actual output 400 units
What is the variable overhead spending variance for the month?

a $112 F
b $130 U
c $4,450 U
d $4,338 U