What amount did (a) his department and (b) each entity reporting to him spend on advertising on the (i) Africa News Network 7 channel, (ii) SA Broadcasting Corporation (aa) television channels and (bb) radio stations, (iii) national commercial radio stations and (iv) community (aa) television and (bb) radio stations (aaa) in the 2015-16 financial year and (bbb) since 1 April 2016?