Answer:
c) labor shortages
Explanation:
In the early 20's when companies and various other organisations faced the problem of labor shortages, that is labor was less than the requirement the companies came up with the scientific approach to management.
Scientific management aims at efficiency and with that greater management of labor productivity.
The early practice of applying the science behind management was started with this, and the observed results were so emphasising, that the practice is followed even now.