Concept:
The river systems of Peninsular India are divided into east-flowing and west-flowing rivers. The Kaveri (or Cauvery) is one of the major east-flowing rivers, and its basin is fed by several important tributaries originating in the Western Ghats.
Step 1: Origin and Course of River Kabini.
The Kabini River (also known as Kapila) originates in the Wayanad District of Kerala as the confluence of the Panamaram River and the Mananthavady River. It flows eastward to join the Kaveri River in Karnataka.
Step 2: Confluence Details.
The Kabini joins the Kaveri at Tirumakudalu Narasipura (T.N. Pur) in Karnataka. This spot is considered a "Triveni Sangam" (confluence of three rivers), where the Kaveri, the Kabini, and the legendary hidden river Spatika meet.
$\text{Confluence Point} = \text{Kaveri} + \text{Kabini} + \text{Spatika}$
Step 3: Environmental Significance.
The river is famous for the Kabini Reservoir and the surrounding Nagarahole National Park. It is a vital water source for the regions of Mysore and Chamarajanagar. Since it eventually drains into the Kaveri, it is classified as a major tributary of the Kaveri river system.
Final Answer: Option C