Answer: (A) Motion economy
Explanation:
The motion economy is the term which refers to the economical movement that improve the various types of methods in an organization. It is also known as the set of rules which improve the work manually and also reduce the fatigue related to the work.
According to the given question, Frank and the Lillian Gilbert is developing the motion economy principle for breaking the job into the different elementary motions.
 Therefore, Option (A) is correct.
