The standard costs and actual costs for factory overhead for the manufacture of 2,500 units of actual production are as follows:

Standard Costs
Fixed overhead (based on 10,000 hours)	3 hours per unit @ $0.79 per hour
Variable overhead	3 hours per unit @ $1.98 per hour
Actual Costs
Total variable cost, $17,800
Total fixed cost, $7,900

The amount of the fixed factory overhead volume variance is

a.$1,580 favorable

b.$0

c.$1,580 unfavorable

d.$1,975 unfavorable