The decreasing order of nucleophilicity among the nucleophiles is :
(I) `CH_(3)-underset(O)underset(||)C-O^(-)`
(II)`CH_(3)O^(-)`
(III) `CN^(-)` (IV)
A. (i), (ii), (iii), (iv)
B. (iv), (iii), (ii), (i)
C. (ii), (iii), (i), (iv)
D. (iii), (ii), (i), (iv)