During the month of January, the standard hours to manufacture product Yare 900 hours while the total actual hours are 1,000 hours out of which 20 hours are idle hours. If the actual rate per hour is OMR 2 and the standard rate per hour is OMR 3.5, calculate the labour efficiency variance. a. 160 favourable b.160 adverse c. 980 favourable d. 980 Adverse Clear my choice