if we see the options in (a) at. No 7 is nitrogen which forms 5 types of oxides in which some of them are neutral so we can’t say it forms acidic oxide and option (b) is at. no 3 which is lithium, it is a metal it forms basic oxide and same goes with option (c) it is magnesium which forms basic oxide too. In option (d) at. no 19 which is chlorine which forms all acidic oxides.