Which of the following is used primarily to identify the occurrence of variation due to...

Statistical process control (SPC) is a method used to monitor and control a process to ensure that it operates at its full potential. One of the primary uses of SPC is to identify the occurrence of variation due to special causes. Special cause variation is unexpected variation that results from specific circumstances, which are not part of the process as designed. SPC utilizes control charts and other statistical tools to detect this type of variation, allowing for timely intervention to correct the process and maintain quality standards1.

References: 2: Manager of Quality/Organizational Excellence Certification CMQ/OE - ASQ. 1: What is Statistical Process Control? SPC Quality Tools | ASQ.