Answer:
D. Natural gas refinery
Explanation:
Processing cost system is when identically units are mass produced. It involves assigning materials, factory labour, overhead cost and so on in an effort to value finished goods inventory. Process cost involves allocation of cost for different set in each process. It helps in determining total cost of producing a unit of commodity. It is best suited for the natural gas refinery because of the various steps involved in the processing and manufacturing of products as cost can be identified and allocated for each steps and also because what is produced are identical units which are mass produced.