Which one is a naturally occuring noble gas? A. Sodium B. Potassium C. Argon D. Boron

The correct answer is $\boxed{\text{C}}$. Argon is a naturally occurring noble gas.

Sodium, potassium, and boron are all elements that are not noble gases. Sodium is a highly reactive metal that is found in nature in the form of salts. Potassium is also a highly reactive metal that is found in nature in the form of salts. Boron is a metalloid that is found in nature in the form of minerals.

Noble gases are elements that are very stable and do not react with other elements. They are all gases at room temperature and pressure. The noble gases are helium, neon, argon, krypton, xenon, and radon.