Answer
(d) pentane
Step-by-step explanation
Volatility is one of the physical properties of alkanes. At room temperature, the unbranched alkanes: methane, ethane, propane, and butane are gases; pentane through hexadecane are liquids; the homologous larger than hexadecane are solids.
Therefore, the alkane that would likely be a liquid at room temperature in the options is:
(d) pentane