Answer:
D) job specialization.
Step-by-step explanation:
Job specialization refers to the concept that as employees (or any individual) develops specific skills needed to perform certain activity, they will become better at performing that activity. Expertise and knowledge on how to better perform a task should enable someone to complete the task in a shorter time, increasing efficiency.
E.g. the first time you drive a car, you are going to make silly mistakes, like everyone else. But a professional car racer that dedicates his/her life to driving will not commit the same errors.