Oil of vitriol is:

Explanation:

Oil of vitriol Is common name of sulfuric acid due to following reasons

It is obtained from the distillation of vitriols mostly green vitriol (FeSO₄7H₂O) Its appearance is oily.

Vitriol contains sulfates of iron and copper.

Final answer: The correct option is (C) sulfuric acid (H₂SO₂)