The "four Ms" of cause-and-effect diagrams are:

material, machinery/equipment, manpower, and methods.

material, methods, men, and mental attitude.

named after four quality experts.

material, management, manpower, and motivation.

mentality, motivation, management, and manpower.

material, machinery/equipment, manpower, and methods.

Explanation:

An ishikawa Diagram, also called the Fishbone Diagram or the Cause-and-effect Diagram is used to perform a cause-and-effect, meaning it is used to show how causes are as a result of causes. Sometimes the fishbone diagrams use the cause and effect method to find root causes and solutions to problems. The bones of the fish are usually the four "Ms" and they are material, machinery/equipment, manpower, and methods. However, sometimes two more Ms are added: Measurement and Mother Nature.