Option 1: Pamba -> A major river in Kerala, flowing through Pathanamthitta district, not in Goa.
Option 2: Zanskar -> A river in the Union Territory of Ladakh, tributary of the Indus River, not in Goa.
Option 3: Ponnani -> A river in Kerala that flows through Palakkad and Malappuram districts, not in Goa.
Option 4: Mandovi -> The largest river in Goa, also known as Mahadayi, flowing through Panaji (the state capital).
Hence, Option 4: Mandovi -> The Mandovi is the lifeline of Goa, flowing westward and emptying into the Arabian Sea. It is crucial for the state's economy, tourism, and transportation. -> correct