correct sequence of reagents to convert P-4 into P-3:
A. (i) Zn , (ii) dil. `H_(2)SO_(4)`
B. (i) Na/`Et_(2)O`, (ii)`B_(2)H_(6)`, (iii) NaOH,`H_(2)O_(2)`
C. (i)Mg(excess)/`Et_(2)O, (ii)O_(2)`(excess), (iii)`NHBH_(4)Cl`(excess)
D. (i) Mg(1 eq.),(ii)`Hg(O Ac)_(2)+H_(2)O`, (iii)` NaBH_(4)`
