Compound X makes warm acidified sodium dichromate(VI) change from orange to green. $1$ mol of X reacts with $2$ mol of $\text{HCN}$ in the presence of $\text{KCN}$. What could X be?
- A$\text{CH}_3\text{CH}_2\text{CH}_2\text{CHO}$
- B$\text{CH}_3\text{COCH}_2\text{COCH}_3$
- C$\text{H}_2\text{C} = \text{CHCH}_2\text{CHO}$
- D$\text{OHCCH}_2\text{CH}_2\text{CHO}$