Ramathan Company produced 6,000 units of Product Y, which is 80% of capacity. Each unit required 0.25 standard machine hour for production. The standard variable factory overhead rate is $5 per machine hour. The actual variable factory overhead incurred during the period was $8,000. The variable factory overhead controllable variance is:

a. $500 favorable.

b. $500 unfavorable.

c. $1,875 favorable.

d. $1,875 unfavorable.