Exhibit 10-4 Zingler Inc. applies variable manufacturing overhead at a standard rate of $9 per direct labor hour. The standard quantity of direct labor is 4 hours per unit. Variable overhead costs totaled $90,000 for the month of December. A total of 15,000 direct labor hours were worked during December to produce 4,000 units. Refer to Exhibit 10-4. Based on this information, what is the variable overhead spending variance? O $54,000 unfavorable O None of the answer choices is correct. $45,000 unfavorable O $45,000 favorable O $54,000 favorable