A large number of poly phosphoric acids and salt arise by

Question

$\begin{array}{1 1} \text {dimerising acidic} DO^{-3}_4 \;units \\ \text{Polymerizing acidic} PO^{-3}_4 \;units \\ \text{Sharing the o atoms at one or two corners of} PO^{-3}_4 units \\ \text{All of the above} \end{array}$