Which of the following is/are compound(s)?

All of these

The correct answer is option 4. All of these

A compound is a substance composed of two or more elements, chemically combined with one another in a fixed proportion.

The constituents can be separated only by chemical or electrochemical reactions.

For example: Water(H₂O), Sugar(C₁₂H₂₂O₁₁), Salt(NaCl), Methane(CH₄) etc