Yo$-$Go Digestive is a manufacturer of a range of dairy products. The following is a list of activities, costs and quantities of activity drivers for a number of activities that occur in the factory.

$\backslash$table$[[$Activity$,$Activity costActivity driver,$\backslash$table$[[$Quantity of$],[$activity driver$]],,],[$Measure ingredients,$$7000,$#batches,$500,$batches$],[$Load machines,$$9200,$#batches,$500,$ batches,$],[$Supervise mixing,$$36000,$#machine hours,$4500,$machine hours$],[$Pack into containers,$$24000,$#litres,$600000$ litres,$],[$Load into refrigeration unit,$10500,$#cartons,$350000$ cartons,$]]$

Under an activity$-$based costing system, what is the activity cost per unit for the activity division of loading the machines?

a$.$ $$0\mathrm{.}05$

b$.$ $$18\mathrm{.}40$

C$.$ $$48\mathrm{.}00$