The correct option is C Among CH3↓CH=O,H3C−↓C≡N, and H3↓C−I
Among CH3↓CH=O,H3C−↓C≡N, and H3↓C−I, the arrow-marked C atoms are electrophilic centers, as they will have partial positive charge due to the polarity of bond.
Hence, they can accept electrons from nucleophile.