Pinnacle Corp. budgeted $$266,640$ of overhead cost for the current year. Actual overhead costs for the year were $$209,460.$ Pinnacle's plantwide allocation base, machine hours, was budgeted at $50,980$ hours. Actual machine hours were $58,640.$ A total of $93,500$ units was budgeted to be produced and $98,000$ units were actually produced. Pinnacle's plantwide factory overhead rate for the current year is:

a$.$ $$2\mathrm{.}85$ per machine hour

b$.$ $$5\mathrm{.}23$ per machine hour

c$.$ $$4\mathrm{.}11$ per machine hour

d$.$ $$2\mathrm{.}24$ per machine hour