[" 30.The true statement for the acids of "],[" phosphorus,"H_(3)PO_(2),H_(3)PO_(3)" and "H_(3)PO_(4)" is "],[[" (a) the order of their acidity is "],[H_(3)PO_(4)>H_(3)PO_(3)>H_(3)PO_(2)],[" (b) all of them are reducing in nature "],[" (c) all of them are tribasic acids "],[" (d) the geometry of phosphorus is "],[" tetrahedral in all the three."]]