For designing a tractor, the assembly line production would entail deciding the sequence of various operations, place for men, machines and raw materials etc. All these are part of:

Method study

The correct answer is Option (3) → Method study

• Method Study (a technique of scientific management) aims to find the "one best way" of doing a job. It involves studying the flow of work, the layout of the workplace, the arrangement of machines, and the sequence of operations to ensure efficient production and minimise production costs. The scenario described—designing the assembly line sequence and layout—is the essence of method study.

• Time Study determines the standard time required to perform a specific task.

• Motion Study eliminates unnecessary movements of workers and machines.

• Work Measurement is a broader term encompassing time study and other techniques used to determine the amount of time required to perform a job.