(b)"competent authority" means [a ] [ Substituted by Act 3 of 1989, Section 48, for " an Assistant Commissioner of Income-tax" (w.r.e.f. 1.1.1988).][Joint Commissioner] [ Substituted by Act 21 of 1998, Section 3, for " Deputy Commissioner" (w.e.f. 1.10.1998).] authorised by the Central Government under section 269-B to perform the functions of a competent authority under this Chapter;