How do monsoons affect the farmers?
During a monsoon, the sun shines brightly, causing the rice fields to grow in abundance.
Monsoons are fierce, torrential rains that can wash their rice away.
Farmers love the monsoons and perform rain dances to make them occur.
Monsoons have no effect on the farmers of India.

B. Monsoons are fierce, torrential rains that can wash their rice away.

Explanation:

Monsoons are extremely powerful and the wind and rain produced during a monsoon can negatively affect a farm by washing or blowing away their crops.  

lemme actually be useful and say i believe the answer is the first one.

dependent clause!

example: "before the food gets cold"