Answer:
C. resources are limited
Step-by-step explanation:
When an economy reaches full employment level, it means all the resources have been utilized in the most efficient manner possible.
So in case of full employment, to increase the production of one commodity, resources have to be diverted from another commodity. This will reduce the production of the commodity from which resources have been diverted.
But, in case of full employment since resources are most efficiently utilized, there are no idle resources.
Hence production of more of commodity A will reduce production of commodity B because (C). resources are limited and scarce.