The purpose of inspection in Perform Quality Control is to keep errors:

According to the PMBOK® Guide, specifically within the Control Quality process (formerly Perform Quality Control), the primary purpose of Inspection is to keep errors out of the hands of the customer.

Definition of Inspection: Inspection is the examination of a work product to determine if it conforms to documented standards. It is often referred to as a " peer review, " " audit, " or " walkthrough. "

The Goal of Control Quality: While " Prevention " (in the Manage Quality process) keeps errors out of the process, " Inspection " (in the Control Quality process) focuses on identifying errors in the final product before that product is delivered to the client.

Verified Deliverables: The result of a successful inspection is a Verified Deliverable. This becomes an input to the Validate Scope process, where the customer formally accepts the deliverable. If the inspection fails, the deliverable is flagged for defect repair to ensure the customer never receives a non-conforming item.

Comparison with Other Options:

In line with a measured degree of conformity (A): This describes the result of the measurement, but " degree of conformity " is more closely related to Precision and Attribute Sampling rather than the fundamental purpose of inspection.

In a specified range of acceptable results (C): This is the definition of Tolerances. While inspection checks if a result falls within a tolerance, the purpose is to catch the outliers before they reach the user.

Out of the process (D): This is the definition of Prevention. Prevention is about designing the process so that errors are not created in the first place. Inspection is the safety net that catches errors that the prevention stage missed.