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

Standard hours per unit of output: $7\mathrm{.}9$ hours

Standard variable overhead rate: $$12\mathrm{.}29$ per hour

The following data pertain to operations for the last month:

Actual hours: $2,700$ hours

Actual total variable overhead cost: $$36,975$

Actual output: $200$ units

What was the variable overhead efficiency variance for the month?

a$.$

$$3,792$ unfavourable

b$.$

$$242$ favourable

c$.$

$$3,009$ unfavourable

d$.$

$$13,765$ unfavourable