Answer:
$0
Explanation:
Under the direct method of cost allocation, each and every service department cost would be distributed to the producing department that depend upon the square footage of space. Also the service of service department would be used by the other service department would not be considered.
So here the custodial service cost would be distributed to the producing department A and producing department b and no cost would be distributed to the general admin department
Hence, the $0 would be allocated