20. If Ferg Company has a $12,000 unfavourable variable overhead efficiency variance, which of the following statements would be TRUE? A B Ferg would credit the Cost of Goods Sold account to write-off the variance. Ferg used the variable overhead components more effectively than expected. C Ferg made efficient use of the cost driver. Ferg used the variable overhead components and cost driver as expected. E Ferg did not use the cost driver efficiently