Correct Option
Assertion (A) states that River Kalinadi is an east-flowing river. This is incorrect. The Kali River, also known as Kalinadi, originates in the Western Ghats of Karnataka and flows westward, eventually emptying into the Arabian Sea. It is a significant west-flowing river of the Peninsular India.
Reason (R) states that the Deccan Plateau is higher along its western edge and gently slopes towards the Bay of Bengal in the east. This statement is factually correct. The Western Ghats form the elevated western margin of the Deccan Plateau, and the general slope of the plateau is eastward, which is why most major peninsular rivers like the Godavari, Krishna, and Cauvery flow towards the Bay of Bengal.
Since Assertion (A) is false and Reason (R) is true, option (d) is the correct choice.
Incorrect Options
Options (a) and (b) are incorrect because they both state that Assertion (A) is true, which is factually inaccurate as Kalinadi is a west-flowing river.
Option (c) is incorrect because it states that Reason (R) is false. The eastward slope of the Deccan Plateau is a fundamental geographical feature of Peninsular India and is true.