Beaver Manufacturing expects to produce 20,000 units next year and has budgeted overhead for the year at $240,000. Over the past four years, Beaver Manufacturing produced the following number of units:Year 1 22,000 Year 2 17,000 Year 3 21,000 Year 4 20,000 Calculate the predetermined overhead rate that Beaver Manufacturing will apply if normal capacity is used. a. $10 b. $14 c. $15 d. $12