The standard costs for XYZ, Inc's only product is as follows: Std Qty/Hours Std Price/Rate Std Cost DM 1.5 gallons $9.00 per gallon $ 13.50 DL .70 hours $21.50 per hour $ 15.05 During the month: a. 31,500 units started and completed b. 49,000 gallons were purchased at $8.50 each, beginning and ending inventory was 0, so all materials were used. c. 23,650 DL hours were worked at a cost of $19.50 per hour Compute the DL efficiency (hours) variance using SR (AH - SH), and note whether U or F.