1 mol of `H_(3)PO_(2), H_(3)PO_(3)` and `H_(3)PO_(4)` will neutralise x mol `NaOH`, y mol of `Ca(OH)_(2)` and z mol of `Al(OH)_(3)` respectively (assuming all as strong electrolytes). x, y, z are in the ratio of:
A. `3 : 1.5 : 1`
B. `1:2:3`
C. `3:2:1`
D. `1:1:1`