Section 3(1)(f) in The Bihar Narcotic Drugs and Psychotropic Substances Rules, 1985
(f)"Collector" means the chief officer incharge of the Revenue administration of a district and includes an officer of the Department of Excise and Prohibition not below the rank of a Superintendent of Excise and any officer empowered by the Government by name or in virtue of his office, to perform all or any of the functions of a Collector under these Rules;