The following data for a pottery company pertain to the production of 2,000 clay pots during July. Direct Materials (all materials purchased were used) Standard cost: $6.00 per kilogram of clay Total actual cost: $11,200 Standard cost allowed for units produced was $12,000 Materials efficiency variance was $240 unfavourable Direct Manufacturing Labour: Standard cost is 2 pots 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? $500 unfavourable $500 favourable $672 favourable $28 favourable $672 unfavourable