$\backslash$table$[[,$Number of$,$Direct Labor Hours,Machine Hours$],[$Product$,$Units,per Unit,per Unit$],[$Rings$,1,020,6,4],[$Dings$,2,690,6,9]]$

The Assembly Department's factory overhead rate $($rounded to the nearest cent$)$ is

a$.$ $$3\mathrm{.}04$ per direct labor hour

b$.$ $$3\mathrm{.}00$ per direct labor hour

c$.$ $$3\mathrm{.}16$ per machine hour

d$.$ $$3\mathrm{.}43$ per machine hour