The following draft annual bud

The following draft annual budget has been prepared for the machining room of a production centre. The machining room makes four components which are then transferred to an assembly and fitting department. The machining room has a maximum capacity of 24,000 hours per year, but any quantity of any of the components can be purchased from an external supplier if required. It is essential that the budgeted quantities of all four components be delivered to the assembly and fitting department. This means that some of the budgeted requirement for components will have to be purchased externally. In order to optimise the financial return, which component should be purchased externally?
A、Component W
B、Component X
C、Component Y
D、Component Z