Sulphur molecule at room temperature is

Octatomic

The correct answer is option 4. Octatomic.

Sulfur molecule at room temperature exists as a cyclic octatomic molecule with the formula S₈. It is a yellow, crystalline solid that is insoluble in water. The sulfur atoms are arranged in a ring with a single bond between each pair of atoms. The octatomic sulfur molecule is the most stable form of sulfur at room temperature.

Diatomic sulfur, tetratomic sulfur, and triatomic sulfur are all unstable forms of sulfur. Diatomic sulfur is a reactive gas that is formed by the dissociation of octatomic sulfur at high temperatures. Tetratomic sulfur is a reactive liquid that is formed by the condensation of diatomic sulfur. Triatomic sulfur is a reactive gas that is formed by the decomposition of octatomic sulfur at very high temperatures.

Therefore, octatomic sulfur is the most stable form of sulfur at room temperature.