Which of the following amines is a gas?

The correct answer is OPTION 4 - All of the above

In organic chemistry, specifically following the NCERT standards, the lower aliphatic amines (Methylamine, Ethylamine, and Dimethylamine) are all colorless gases at room temperature. They possess a characteristic fishy odor. Amines with three or more carbon atoms are typically liquids, and even higher members are solids. Since all three specific options listed have two or fewer carbons, they all exist as gases.