The correct option is (a).
Explanation
The transport system in the Ganga-Brahmaputra basin is heavily influenced by its topography. The vast flat plains support dense human settlements and infrastructure, while the river systems provide opportunities for inland navigation.
Statement 1 is Correct:
The plain areas of the basin possess flat and level terrain, which is ideal for the construction of infrastructure. Consequently, roadways and railways are well-developed and form a dense network connecting the highly populated regions of the plains.
Statement 2 is Incorrect:
Kolkata is a major riverine port, but it is specifically located on the banks of the River Hooghly, which is a distributary of the Ganga. While it is part of the Ganga system, geographically precise statements distinguish between the main river channel and its distributaries.
Statement 3 is Incorrect:
The assertion that the plain area lacks air connectivity is factually wrong. The region is well-connected by air, hosting numerous major airports in cities such as Kolkata, Patna, Lucknow, Guwahati, and New Delhi.
Key Takeaway:
The Ganga-Brahmaputra plains feature a highly developed network of roadways and railways due to favorable terrain. Kolkata is a riverine port situated on the River Hooghly. The region has significant air connectivity.