The Correct answer is Option 3. Explanation & Key Takeaways: • The passage explains that carbon can form a very large number of compounds because of two important properties: tetravalency and catenation. • Tetravalency means that a carbon atom has four valence electrons and can form four strong covalent bonds with other atoms such as carbon, hydrogen, oxygen, nitrogen, and others. This allows carbon to create a wide variety of stable molecules. • Catenation is the ability of carbon atoms to bond with one another, forming long chains, branched chains, and ring structures. Because of this property, carbon can form simple molecules as well as very complex structures. • These two properties together make carbon capable of forming more compounds than any other element. Therefore, the correct answer is Tetravalency and catenation.