Calcium oxide reacts vigorously with water to produce slaked lime.$\mathrm{CaO}(s) + \mathrm{H}_2\mathrm{O}(l) \rightarrow \mathrm{Ca(OH)_2}(aq)$This reaction can be classified as :(A) Combination reaction(B) Exothermic reaction(C) Endothermic reaction(D) Oxidation reactionWhich of the following is a correct option ?(a) (A) and (C)(b) (C) and (D)(c) (A), (C) and(D)(d) (A) and (B)ORWhen hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of a :(a) Combination reaction(b) Displacement reaction(c) Decomposition reaction(d) Double displacement reaction