Which of the following statements regarding sulphur is not correct?

Which is the stable crystalline form of sulfur at room temperature?

Assertion : There is a large difference between the melting and boiling points of $O$ and $S$.
Reason : It can be explained on the basis of their atomicity in $O_2$ and $S_8$ molecules.

An amorphous solid $'A'$ burns in air to form a gas $'B'$ which turns lime water milky. The gas is also produced as a by-product during roasting of sulphide ore. This gas decolourises acidified aqueous $KMnO_4$ solution and reduces $Fe^{3+}$ to $Fe^{2+}$. Identify the solid $'A'$ and the gas $'B'$ and write the reactions involved.

Assertion : Reaction of $SO_2$ and $H_2S$ in the presence of $Fe_2O_3$ catalyst gives elemental sulphur.
Reason : $SO_2$ is a reducing agent.

Explain the trends in oxidation states and chemical reactivity of Group $16$ elements.