The correct option is The Arakan Hills along the coast of Myanmar..
Explanation
The Southwest Monsoon approaches the Indian landmass in two distinct branches: the Arabian Sea branch and the Bay of Bengal branch. The direction of flow and the subsequent distribution of rainfall are significantly influenced by the orography (relief features) of the surrounding regions.
Detailed Analysis:
- The Andaman and Nicobar Islands. is incorrect: The Andaman and Nicobar Islands are located within the path of the Bay of Bengal branch and receive rainfall from it. However, they lack the continuous high-altitude relief required to deflect the massive wind system towards the Indian mainland.
- The Arakan Hills along the coast of Myanmar. is correct: The Bay of Bengal branch initially advances towards the coast of Myanmar and southeast Bangladesh. The Arakan Yoma (Arakan Hills), located along the coast of Myanmar, act as a formidable physical barrier. These mountains obstruct the eastward passage of the winds and deflect a significant portion of the branch towards the Indian subcontinent. Consequently, the winds enter West Bengal and Bangladesh from the south and southeast, moving into the Gangetic plains.
- The high pressure over the Bay of Bengal. is incorrect: The monsoon flow is driven by a pressure gradient established by intense low pressure over the Indian subcontinent and relatively higher pressure over the Indian Ocean. While pressure drives the wind, the specific deflection of the wind direction towards the northern plains is caused by physical barriers (orography), not by high pressure over the Bay of Bengal.
- The Western Ghats. is incorrect: The Western Ghats are located along the western coast of India. They act as a barrier to the Arabian Sea branch of the monsoon, causing orographic rainfall along the western coast, but they do not influence the deflection of the Bay of Bengal branch entering from the east.
Key Takeaway: The Arakan Hills (Arakan Yoma) are the primary orographic feature responsible for deflecting the Bay of Bengal branch of the monsoon westwards and north-westwards into the Indian subcontinent.