The increaing order of the rate of HCN addition to compound A-D is : <br> (A) $HCHO$ <br> (B) $CH_3COCH_3$ <br> (C) $PhCOCH_3$ <br> (D) $PhCOPh$

Question

( A ) A < B < C < D
( B ) D < C < B < A
( C ) C < D < B < A
( D ) D < B < C < A