Section 3(1)(a) in The Central Sales Tax (Registration and Turnover) Rules, 1957
(a)signed by the proprietor of the business, or, in the case of a firm, by one of its partners, or, in the case of a Hindu Undivided Family, by the Karta or manager of the family, or, in the case of a company, by a director, managing agent or principal officer thereof, or, in the case of a Government, by an officer duly authorised by that Government, or, in the case of any other association of individuals, by the principal officer managing the business; and