The correct option is 1 and 3 only
Explanation
The Son River is a significant river of the Peninsular Drainage System that flows northward to join the Ganga. It is the principal right-bank tributary of the Ganga originating from the Peninsular Plateau.
Statement 1 is Correct:
The Son River originates from the Amarkantak Plateau in Madhya Pradesh. It flows generally in a northeast direction and is a large south bank (right bank) tributary of the Ganga.
Statement 2 is Incorrect:
The river does not flow through a completely flat terrain throughout its course. It traverses the rugged terrain of the Peninsular Plateau and cuts through the Kaimur Range. Due to the steep gradient in its upper and middle reaches, the river forms waterfalls and cascades before entering the plains.
Statement 3 is Correct:
The confluence of the Son River with the Ganga occurs near Maner, which is located to the west of Patna, Bihar.
Key Takeaway:
The Son River is a major right-bank tributary of the Ganga that originates from the Amarkantak Plateau, unlike the left-bank tributaries which primarily originate in the Himalayas.