Concept:Petroleum drilling loses its importance when there is no longer enough petroleum to justify the drilling process.
Explanation:Drilling is carried out mainly to extract petroleum from underground reserves.
If reserves are depleted, little or no petroleum remains for extraction, so drilling becomes unimportant.
On the other hand, adequate capital supports drilling by funding equipment and operations.
Adequate skilled labour ensures drilling is done efficiently and safely.
Good management helps plan and coordinate drilling activities successfully.
Therefore, only depletion of reserves can make petroleum drilling unimportant.
Answer:A. Depletion of reserves