Mark recommends that the managers at statco should identify how and why performance has deviated beyond the acceptable range of variation, and then correct the source of the deviation. here, mark is recommending

basic corrective action

Explanation:

Basic corrective action refers to the identification of the cause of the problem and then solving the problem by correcting or eradicating the root cause. On the other hand, the intermediate corrective action only solves or corrects the problem at hand rather than identification of the root cause and then solving or correcting the cause. Here, the answer is basic corrective action as Mark is said to recommend the managers to identify how and why performance has deviated.

the answer is d.index