A firm follows machine hours to allocate machine related variable overhead. During the month, the firm reported adverse variable overhead spending variance and favorable variable overhead efficiency variance. It means?

A. The firm took more hours than standard hours but controlled machine expenses

B. The firm controlled machine hours but incurred more expense on operating the machine

C. Firm failed on both controlling machine hours and cost but production volume increases

D. Firms controlled machine hours, controlled expenses but production volume declined