- (a) The Banking Companies (Acquisition of Undertakings) Ordinance, 1980, led to the nationalization of six more banks in April 1980. - (b) The Special Bearer Bonds, 1981 scheme was introduced to mobilize resources and unearth black money. - (c) The Unlawful Activities (Prevention) Act was enacted in 1967. While the question asks for an ordinance and lists 1966, this pairing is the most plausible match given the other confirmed dates and options. It is likely referring to legislative activity preceding the 1967 Act or a related ordinance from that period. - (d) The Terrorist Affected Areas (Special Courts) Ordinance was promulgated in 1984.