MNO produces a single product. The standard production requirement for each unit requires 0.50 direct labour hours at a standard rate of $15 per hour. During the last year, MNO assembly line workers worked a total of 2,000 hours at a cost of $60,000 to MNO. Also last year, MNO manufactured 3,000 units of product. What was the company's direct labour efficiency variance for the year?

a)Nill

b) $4000 favourable

c) $7500 unfavourable

d) $1650 unfavourable