The following data for Serena Company pertain to the production of 2,000 wood cups during March. Direct Materials (all materials purchased were used): Standard cost: $6.00 per kilogram of wood Total actual cost: $11,200 Standard cost allowed for cups produced was $12,000 Materials efficiency variance was $240 unfavourable Direct Manufacturing Labour: Standard cost is 2 cups per hour at $24.00 per hour Actual cost per hour was $24.50 Actual labour was 972 hours What is the direct manufacturing labour efficiency variance? A) $500 unfavourable B) $672 unfavourable C) $500 favourable D) $28 favourable E) $672 favourable