The standard direct labour cost of product z is as follows: four hours of grade b labour at £3 per hour is equal to £12 per unit of product z. during period four, 900 units of product z were made, and the direct labour cost of grade c labour was £9,400 for 2,000 hours of work. based on the above information, what was the total direct labour variance?

a) £1,110 adverse
b) £1,400 adverse
c) £1,100 favourable
d) £1,400 favourable