Please provide the correct answer to this general accounting problem using valid calculations.

Precision Parts Manufacturing allocates manufacturing overhead based on machine hours. Each component is expected to require 6 machine hours. According to the static budget, Precision Parts expected to incur the following: 1. 600 machine hours per month (components * 6 machine hours per component). 2. $7,800 in variable manufacturing overhead costs. 3. $12,000 in fixed manufacturing overhead costs. During July, Precision Parts actually used 550 machine hours to make 100 components, spending $7.200 in variable manufacturing overhead costs and $12,100 in fixed manufacturing overhead costs. Precision Parts" standard variable manufacturing overhead allocation rate is: a. $13 per machine hour b. $12.50 per machine hour c. $14.67 per machine hour d. $11.25 per machine hour