Solution
Option 1 -> Fatigue study involves analyzing when workers tire during work to determine optimal rest intervals and working hours, not related to rewards for output.
Option 2 -> Motion study examines the body movements required to perform a task to eliminate unnecessary motions and improve efficiency, not about compensation based on output.
Option 3 -> Simplification of work focuses on reducing product varieties and standardizing processes to minimize complexity, not about rewarding performance.
Option 4 -> Differential piece wage system is a wage incentive plan where workers receive different wage rates based on whether they meet or exceed the standard output level.
Hence, Option 4: Differential piece wage system -> This technique by F.W. Taylor provides higher wages to efficient workers who meet/exceed standard output and lower wages to those who don't, directly matching the concept of rewarding employees for meeting standard output mentioned in the statement -> correct