Which one of the following statements is correct regarding ‘Zonal councils?
(a) They are executive bodies constituted under the orders of the Ministry of Home Affairs. (b) Each Zonal council consists of all Members of Parliament from that zone. (c) Each chief minister acts as a vice-chairman of the council by rotation for a period of one year at a time. (d) They are empowered with investigating powers on subjects in which the states or the Centre have a common interest.