What is the oxidation no. of phosphorus in H4P2O7 , H5P3O10, (HPO3)3 or pyrophosphoric acid, penta phosphoric acid, triphosphoric acid respectively ?
(a) +4, +5, +3
(b) +6, +5, +5
(c) +5. +5, +5
(d) +4, +5, +5
