Section 103(1)(a) in The Bihar (Coal Mining) Area Development Authority Act, 1986
(a)where the document is to be served on a Government Department, railway, local authority, statutory authority, company, corporation, society or other body, if the document is addressed to head of the Government Department, General Manager of the Railways, Local Authority, Statutory Authority, Company, Corporation, Society or any other body at its principal branch, local or registered office, as the case may be, and is either-(i)sent by registered post to such officer, or(ii)delivered at such officer.