Answer: 8 weeks
Explanation:
As soon as one starts exercise the effect is not visible on their body.The effect of exercise on the human body can be observed only when the exercise is performed for at least 8 weeks.
The human body needs time to adjust with the changing lifestyle and adapt the new one.
Exercising for at least two months will aid in visible difference in the body of the human beings.
So, the correct answer is Option B