department rate system for allocating overhead. The following table presents information about estimated overhead and direct labor hours.

$\backslash$table$[[,$overhead,$\backslash$table$[[$Direct$],[$Labor Mours $($dlh$)]],$Produet$],[,$A$,$B$],[$Palnting Dept.,$$248,000,10,000dlh,16$ dlh$,4$ dlh$],[$Finishing Dept,$72,000,10,000,4,16],[$Totals$,$$$320,000,20,000dlh,20$ dlh$,20$ dlh$]]$

Using a single plantwide rate, the factory overhead allocated per unit of Product B is

a$.$ $$496$

b$.$ $$640$

c$.$ $$144$

d$.$ $$320$