Contract MFG or OSP - which will be more suitable in this scenario

Summary:

Contract MFG or OSP - which will be more suitable in this scenario

Content (please ensure you mask any confidential information):

There are 3 entities (A, B, C) other than OEM (X).

OEM supplies all raw materials to the suppliers **** manufacturers. 

OEM pays for the manufacturing services to Suppliers. 

2 suppliers (A, B) are manufactueres as well as warehouses (storage).

3rd entity (C) is a Warehouse.

Output of A goes into B as an RM and Output of B goes into C as an FG that is stored 

and shipped to Customer.

OEM owns all the RM, Semi-FG, FG all across.