Answer:
A. Refining is the correct answer.
Step-by-step explanation:
Refining step occurs next after extraction in the mineral resource cycle.
Refining is the method of decreasing the impurities in the substance.
Extraction is the initial step to isolate the desired products from the raw substances.
After the extraction process is completed the final step is refining in which impurities are removed.
Thus Refining leaves the main element in a pure form for the commercial utilization.