AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Option A — Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Carbon's tetravalency and catenation together enable it to form millions of compounds, more than all other elements combined.
The textbook explicitly states: "The two characteristic features seen in carbon, that is, tetravalency and catenation, put together give rise to a large number of compounds." Both the assertion (carbon forms the most compounds) and the reason (catenation + tetravalency) are correct, and the reason directly explains the assertion — so option A is the answer. Examiners look for you to confirm both statements are true and that R correctly explains A.