The correct option is (c).
Explanation
The months of October and November are known for the retreating monsoons. During this period, the apparent movement of the sun towards the south causes the monsoon trough or the low-pressure trough over the Northern Plains to become weaker.
Statement-wise Analysis:
- Statement 1 is Incorrect: The low-pressure trough over the northern plains does not intensify; rather, it weakens and is gradually replaced by a high-pressure system. The low-pressure conditions transfer to the Bay of Bengal by early November, often creating cyclonic depressions.
- Statement 2 is Correct: The retreat of the monsoon is marked by clear skies and a rise in temperature. As the rains cease, the clouds dissipate, allowing for increased solar insolation.
- Statement 3 is Correct: While the days are warm, the nights are cool and pleasant. However, the land is still moist. Owing to the conditions of high temperature and humidity, the weather becomes oppressive during the day. This phenomenon is commonly known as 'October heat'.
Key Takeaway:
The retreating monsoon season is characterized by the replacement of the low-pressure trough over the plains with high pressure, clear skies, and the oppressive weather condition known as 'October heat'.