Answer: Option (C) is the correct answer.
Explanation:
A covalent compound is formed by sharing of electrons between two chemically combining atoms.
A covalent bond will always form between non-metals.
Some properties of covalent compounds are as follows.
As covalent compounds have low melting and boiling point so, it is possible that they evaporate at room temperature.
Thus, we can conclude that sample C is a liquid that evaporates at room temperature, most likely to be a covalent compound.