A,B and C are hydroxy-compounds of the elements X, Y and Z respectively. & Y and Z are in the same period of the periodic table. A gives an aqueous solution of pH less than seven. B reacts with both strong acids and strong alkalies. C gives an aqueous solution which is strongly alkaline.Which of the following statements is,/are true ?I : All the three elements are metals.II : The electronegativities decrease from X to Y to Z.III : The atomic radius decreases in the order X, Y and Z.lV : X, Y and Z could be phosphorus, aluminium and sodium respectively.