A Dry Cleaner Currently Has 10 Workers and 4 Machines

Multiple Choice

A dry cleaner currently has 10 workers and 4 machines.The workers' wage rate is $300 per worker and the rental rate for a machine is $500.The last worker added 600 units to total output
And the last machine also added 600 units to total output,and the last machine also added 600 units to total output.If the dry cleaner uses 11 workers and 3 machines instead,then

A) cost will be unchanged and output will increase by 300 units.
B) cost will be unchanged and output will decrease by 200 units.
C) output will be unchanged and cost will decrease by $500.
D) output will be unchanged and cost will decrease by $200.
E) none of the above