The correct option is (a).
Explanation
The Mahanadi is a major east-flowing river of the Peninsular drainage system. It is distinct from other major peninsular rivers in terms of its origin in the Central Highlands rather than the Western Ghats.Statement 1 is Correct: The total length of the Mahanadi river is approximately 851 km (often rounded to about 860 km in standard texts). It flows through the states of Chhattisgarh and Odisha before draining into the Bay of Bengal.
Statement 2 is Incorrect: The drainage basin of the Mahanadi extends over the states of Chhattisgarh, Madhya Pradesh, Odisha, Jharkhand, and Maharashtra. The states mentioned in the statement-Karnataka, Kerala, and Tamil Nadu-constitute the drainage basin of the River Cauvery.
Statement 3 is Incorrect: The Mahanadi rises near Sihawa in the Raipur district of Chhattisgarh. It does not originate in the Western Ghats. Conversely, rivers such as the Godavari, Krishna, and Cauvery have their sources in the Western Ghats.
Key Takeaway: The Mahanadi originates in the highlands of Chhattisgarh and its basin covers Central and Eastern India, whereas the Cauvery basin covers the southern states of Karnataka, Tamil Nadu, and Kerala.