Which one of the following is a compound ?

Which one of the following is a compound ?

Milk
Sugar
Tea
Coffee
This question was previously asked in
UPSC CAPF – 2010
Among the given options, Sugar is a compound.
A compound is a substance formed when two or more different chemical elements are chemically bonded together in a fixed proportion. Milk, Tea, and Coffee are all mixtures. They consist of various substances physically mixed together, not chemically bonded in fixed ratios. “Sugar” typically refers to sucrose (C₁₂H₂₂O₁₁), which is a molecule composed of atoms of carbon, hydrogen, and oxygen chemically bonded in a fixed ratio, making it a compound.
A mixture is a substance consisting of two or more components not chemically combined. The components of a mixture retain their individual properties and can often be separated by physical means. Examples include air (mixture of gases), salt water (salt dissolved in water), milk, tea, and coffee.