Heavy rain. Mud is water and soil. The other options don't make sense. Also, it's kind of obvious this is from a multiple choice question.
The heavy rains caused a mudflow. The mudflow came down the hill and hit the village.
After a heavy rain
Mudflow
A mudflow is caused when there is lots of loose mud and ground water. This ground water can come from heavy periods of rainfall or snow melt. There also is a lack of vegetation so the soil is not held in place and it is usually on a slope above 10 degrees. There is also Saturated soil which flows over impermeable sub soil.
Or Mudslide because there both the same thing
1. Heavy Rain 2. Strong Winds 3. Lightning 4. Thunder 5. Tornado
Strong heavy waves
Lot's of rain and cold weather causes heavy snow.
The rain seeps into the microscopic spaces between the soil particles. This turns the hillside into a thick liquid - which slides downhill due to gravity.
Latent heat from evaporated ocean water
The type of weather front that cause the most violence is a cold front. They can contribute to strong winds, major thunderstorms, and heavy rain.
Strong winds that cause heavy rain and flooding are called hurricanes.