Sleepy's mattress factory's budgeted sales were 500 mattresses with a budgeted sales price of $300 and a budgeted unit variable cost of $140. Actual sales for the month of January were 450 mattresses, actual sales price was $320, and actual unit variable cost was $150. Calculate the activity variance for January. A $9,000 Favorable B $9,000 Unfavorable C) $8,000 Favorable D) $8,000 Unfavorable