Because when there is a famine no crops were grown so when people don't get food they not alive that's why when famine comes in bengal the 1/3 population wiped out.

Introduction:
Bengal, a region in the eastern part of the Indian subcontinent, has faced numerous challenges throughout its history. One of the tragic events that decimated a significant portion of the population was a terrible famine. This answer aims to explain why option 'A' - a terrible famine - is the correct answer.

Explanation:
1. Bengal Famine:
- The Bengal Famine occurred in the early 1940s during World War II.
- It was a severe famine that affected the Bengal province, comprising present-day West Bengal (India) and Bangladesh.
- The famine was primarily caused by a combination of natural and man-made factors.

2. Natural Factors:
- A major factor contributing to the famine was a series of natural disasters, including drought, cyclones, and floods.
- These calamities led to a significant decline in agricultural production, destroying crops and causing food shortages.

3. Man-made Factors:
- The man-made factors that worsened the famine included policies imposed by the British colonial government.
- The British government requisitioned rice, which was the staple food of the region, to support the war effort.
- This policy severely disrupted the local food supply and exacerbated the already dire situation.

4. Impact on the Population:
- As a result of the famine, a large number of people in Bengal were deprived of adequate food and nutrition for an extended period.
- Many people succumbed to starvation, while others fell victim to diseases and malnutrition.
- The death toll was staggering, with approximately one-third of the population wiped out during this period.

Conclusion:
The correct answer for the question is option 'A' - a terrible famine occurred there. The Bengal Famine of the 1940s, caused by a combination of natural disasters and man-made policies, led to widespread food shortages and resulted in the death of approximately one-third of the population in Bengal. This tragic event had a profound impact on the region and its people, leaving a lasting scar in the history of Bengal.