Option 1 -> Imphal is the capital of Manipur, not associated with the Tlawng river.
Option 2 -> Aizawl is the capital of Mizoram, where the Tlawng river flows through.
Option 3 -> Agartala is the capital of Tripura, located in a different northeastern state.
Option 4 -> Itanagar is the capital of Arunachal Pradesh, not connected to the Tlawng river.
Hence, Option 2 (Aizawl) -> The Tlawng river is one of the major rivers in Mizoram and flows through its capital city Aizawl. It is also known as Dhaleshwari river when it enters Bangladesh -> correct