Answer:
Correct option is C.
$0.72
Step-by-step explanation:
The following information about in-house manufacturing is given: 
Wage = $22.50 per hour per person 
Production = 1000 
Number of workers = 4 
Total number of hours = 8 
Variable cost is the cost which changes with the change in level of production. For example cost of labour. 
Total cost of labour = $22.50 x 4 x 8 =$720 
Cost per carton is calculated as follows: 
Total cost Cost per carton /Total production= $720/1000 
=$0.721