In the last four$-$week period, the $20$ sales staff in the telephone sales department of a company made $14100$ calls to potential customers.

The standard time for a call is $10$ minutes and the staff work a $35$ hour week, of which five hours are made up of rest or breaks. The standard cost per call is $$5\mathrm{.}00.$

What is the labour efficiency variance for the last four$-$week operating period?

$\backslash$table$[[$A$,[,],[$B$,[,$$$1500$ Favourable$],[$C$,$ Adverse,$],[$D$,[,$$$13500$ Favourable$],[,$$$13500$ Adverse,$]]$