Which of the following is a polyatomic element?

So, here argon and helium are the noble gases or, we can say that they are the monatomic elements but the sulphur and phosphorus are the polyatomic elements.

Monoatomic elements are in the form of single molecule form so they are not polyatomic elements.

And it is noted that all the metals and some other elements like carbon do not have simple structure and their atomicity is not defined so we considered the atomicity of these elements as 1.

The sulphur and phosphorus is represented by  respectively.

So, from above options sulphur and phosphorus are the polyatomic elements.

Hence the correct option is A) Sulphur and B) Phosphorus.