The tax payable under the Act shall be calculated on the basis of-

(a) The sale price of the goods at such rate not exceeding fifty percent; or

(b) The weight or volume of the goods at such rate not exceeding fifty rupees per litre; or

(c) Any combination of clause (a) or (b)

as the State Government may, by notification, specify and subject to such conditions and restrictions as may be specified in the said notification.