Step 1: Understand the geographical context.
Siliguri is a city in West Bengal, strategically located in a narrow strip of land known as the "Siliguri Corridor" or "Chicken's Neck." This location makes it a crucial transit point connecting mainland India with its northeastern states and neighboring countries like Nepal, Bhutan, and Bangladesh.
Step 2: Know the route of National Highway 10 (NH 10).
The primary route of NH 10 starts in Siliguri and runs north to Gangtok, the capital of Sikkim. This makes it the lifeline of Sikkim.
Step 3: Identify the connection to Bangladesh.
A major road branches off from NH 10 at the Phulbari area near Siliguri. This branch leads directly to the Phulbari-Banglabandha border crossing, which is a key land port for trade and transit between India and Bangladesh. Therefore, NH 10 is the highway that provides the connection to Bangladesh *from the Siliguri area*.
Step 4: Rule out other options.
NH 44 is the longest highway in India, running from North to South (Srinagar to Kanyakumari).
NH 27 is the main East-West corridor (Porbandar to Silchar).
NH 16 runs along India's east coast (Kolkata to Chennai).
None of these other highways serve the specific Siliguri-to-Bangladesh border route.