नीचे दो कथन दिए गए हैं: कथन I: 'याजू नदी' (Yazoo stream) एक ऐसी सहायक नदी है जो प्राकृतिक तटबंधों के कारण मुख्य नदी के समानांतर काफी दूरी तक बहती है। कथन II: प्राकृतिक तटबंध बाढ़ के समय नदी के तटों के साथ निर्मित होने वाली निक्षेपात्मक भू-आकृतियाँ हैं। उपरोक्त कथनों के आलोक में सही उत्तर चुनें:

Given below are two statements, one labelled as Assertion (A) and the other as Reason (R): Assertion (A): The valley sides and valley floors of rivers are vigorously eroded through abrasion in hilly regions. Reason (R): A steep channel gradient accelerates the abrasive power and erosive capacity of rivers. Select the correct answer:

Consider the following Assertion (A) and Reason (R): Assertion (A): Impoundment of a river by a dam decreases its downstream sediment entrainment capacity. Reason (R): Water velocity drops inside a reservoir, causing sediment deposition before water is released downstream. Select the correct option: