Which one among the following is not a west-flowing river?

The Banas River is an east-flowing river. It originates in the Khamnor Hills of the Aravalli Range in Rajasthan and is a major tributary of the Chambal River. The Chambal joins the Yamuna, which eventually merges with the Ganga, draining into the Bay of Bengal.

• Mahi: Rises in the Vindhya Range (Madhya Pradesh) and flows west through Rajasthan and Gujarat into the Gulf of Khambhat.
• Luni: Originates in the Pushkar Valley of the Aravalli Range. It flows west/southwest and terminates in the Rann of Kutch. It is the largest inland river in Rajasthan.
• Sabarmati: Originates in the Aravalli Range (Udaipur, Rajasthan) and flows south-west through Gujarat, emptying into the Gulf of Khambhat.

Note: While a smaller "West Banas" river exists, the name "Banas" typically refers to the significant Chambal tributary belonging to the Ganga drainage system.