The correct answer is A. South-West monsoon.
The South-West monsoon is a seasonal wind that blows from the Indian Ocean towards the Indian subcontinent. It is responsible for most of the rainfall in India, including Haryana. The monsoon winds are caused by the difference in temperature between the land and the ocean. During the summer, the land heats up faster than the ocean, creating a low-pressure system over the land. This low-pressure system draws in moist air from the ocean, which rises and cools, causing the formation of clouds and rain.
The South-West monsoon arrives in India in June and stays until September. The intensity of the monsoon varies from year to year, but it is generally a reliable source of rainfall for the Indian subcontinent.
The other options are incorrect because they are not the main cause of rainfall in Haryana.
- Eastern winds are not a major factor in the rainfall in Haryana. They are a type of wind that blows from the east towards the west. They are not as strong as the South-West monsoon winds and they do not bring as much rain.
- Western disturbances are a type of weather system that forms over the Mediterranean Sea. They can bring rain to Haryana, but they are not as common as the South-West monsoon.
- Cold waves are a type of weather system that brings cold air from the north. They can cause temperatures to drop below freezing in Haryana, but they do not bring much rain.