The primary objective of control charts is (a) To evaluate process mean and spread with reference to specification limits. (b) To assess the process for stability. (c) to stop the process when defect...

(a) To evaluate process mean and spread with reference to specification limits.

(b) To assess the process for stability.

(c) to stop the process when defect is observed.

(d) To ensure that the process is set correctly at the mean of specifications.