Reece Enterprises machines heavy$-$duty brake rotors that are used on commercial airliners. The company's management developed the following standard costs:

Standard direct labor hours per rotor $1\mathrm{.}9$

Standard overhead rate per direct labor hour $$10\mathrm{.}75$

Actual activity for October:

Actual overhead costs incurred $$124,800$

Actual direct labor hours $10,400$

Actual rotors machined $3500$

What is the variable manufacturing overhead rate variance in October?

$$13,000$ favorable

$$40,313$ unfavorable

$$40,313$ favorable

$$13,000$ unfavorable