Ecocomfort Corporation manufactured 1,000 cooling units during May 2021. This is the relevant information for May: Variable overhead spending variance $ 1,230 Unfavorable Variable overhead efficiency variance $ 175 Unfavorable Budgeted machine hours allowed for actual output 615 machine hours Actual cost per machine hour $ 27 Budgeted cost per machine hour $ 25 Calculate the current machine hours used by EcoComfort during May 2021.

a.615 hours

b.608 hours

c.620 hours

d.622 hours