Sulfur dioxide can be properly classified as a/an -
a. acid anhydride
c. basic anhydride
b: anhydrous salt
d. hydrate​

Explanation:

A. Acid anhydride

Anhydride because it does not have water molecule in it

Chemical Classification: Inorganic substances.

Summary: Sulfur dioxide is a colorless gas with a pungent odor. It is a liquid when under pressure, and it dissolves in water very easily. Sulfur dioxide in the air comes mainly from activities such as the burning of coal and oil at power plants or from copper smelting.