Ella Corporation's flexible budget performance report for last month shows that actual indirect materials cost, a variable overhead cost, was $30,284 and that the variance for indirect materials cost was $1,808 unfavourable. During that month, the company worked 11,300 machine-hours, Budgeted activity for the month had been 11,400 machine-hours. The cost formula per machine-hour for indirect materials cost must have been closest to: Select one: a. $2.84 b. $2.52 C. $2.50 d. $2.82