Answer:
C. Correct, because for the work to be carried out in 5 days, 40 workers are required.
Explanation:
The job requires 10 people to work for 20 days. That's 200 worker-days.
In other words,
days × workers = 200 or
workers = 200/days
To get the work done in five days,
workers = 200/5 = 40.
You must hire 40 workers.
B. and D. are wrong. To get the job done in seven days. you must hire 200/7 = 29 workers.