What is referred to as the 'terror of Bengal'?

Water Hyacinth

The correct answer is Option (3)-Water Hyacinth

The term 'terror of Bengal' refers to the aquatic plant water hyacinth. This plant is highly invasive and is known for its rapid vegetative propagation, which allows it to spread quickly over water bodies. Water hyacinth can cover entire surfaces of lakes and ponds, blocking sunlight and depleting oxygen levels in the water, which leads to the death of aquatic life, particularly fish. It was introduced to India due to its attractive flowers and leaves, but its aggressive growth and ecological impact have made it a significant environmental concern, particularly in regions like Bengal.