The following data relate to direct labor costs for March: Rate: standard, $12.00; actual, $12.25 Hours: standard, 18,500; actual, 17,955 Units of production: 9,450 The direct labor time variance is Oa. $6,540.00 favorable Ob. $2,362.50 unfavorable Oc. $6,540.00 unfavorable Od. $2,362.50 favorable