Cox Engineering performs cement core tests in its laboratory. The following standards have been set for each core test performed: Direct materials * Standard hours/quantity 3 pounds * Standard price/rate $0.75 per pound Direct labor * Standard hours/quantity 0.4 hours * Standard price/rate $12 per hour Variable manufacturing overhead * Standard hours/quantity 0.4 hours * Standard price/rate $9 per hour During March, the laboratory performed 2,000 core tests. On March 1 no direct materials (sand) were on hand. Variable manufacturing overhead is assigned to core tests on the basis of direct labor hours. The following events occurred during March: * 8,600 pounds of sand were purchased at a cost of $7,310. * 7,200 pounds of sand were used for core tests. * 840 actual direct labor hours were worked at a cost of $8,610. * Actual variable manufacturing overhead incurred was $3,200. The labor rate variance for March is 1. $4,578 unfavorable 2. $1,470 UNFAVORABLE 3. $4,578 FAVORABLE 4. $1,470 FAVORABLE