The following data pertain to activity and costs for two recent months: June July Unit sales 15,000 10,000 Sales price / unit $15 $15 Variable costs (total) $ 45,000 ?? Fixed costs (total) $ 60,000 ?? Mixed costs (total) $ 22,000 ?? Total costs $127,000 $105,000 Assuming that these activity levels are within the relevant range, the mixed costs for July were: Select one: a. $ 0 b. $15,000 c. $22,000 d. $25,000