Which of the following states of India receives initial rainfall by the Arabian Sea branch of monsoon?

The correct answer is Kerala.

Step-by-Step Explanation:

1. Understanding the Southwest Monsoon:
The monsoon winds that bring rainfall to India during the summer months (June to September) originate from the southwest direction. This monsoon is divided into two main branches due to the peninsular shape of India:
- The Arabian Sea Branch
- The Bay of Bengal Branch

2. The Arabian Sea Branch:
The Arabian Sea branch of the southwest monsoon approaches the Indian landmass from the southwest. It first hits the Western Ghats (a mountain range along the western coast of India).

3. First Point of Onset:
Because Kerala is located on the southwestern tip of the Indian peninsula, it is the first mainland state in India to receive rainfall from the Arabian Sea branch of the monsoon. This typically happens in the first week of June (often around June 1st).

4. Analyzing the Options:
- Kerala: Located on the southwest coast, directly in the path of the incoming Arabian Sea branch. It receives the initial rainfall.
- Mizoram & Assam: Located in Northeast India, which primarily receives monsoon rains from the Bay of Bengal branch.
- Tamil Nadu: Located on the southeastern coast (coromandel coast). It lies in the rain shadow region of the Western Ghats during the southwest monsoon, receiving most of its rainfall from the retreating (Northeast) monsoon later in the year.

Therefore, Kerala is the Indian state that receives initial rainfall by the Arabian Sea branch of the monsoon.