Compound X has molecular formula C$_3$H$_6$O$_3$. When X is heated under reflux with acidified K$_2$Cr$_2$O$_7$, HO$_2$CCOCO$_2$H is formed. If X reacts with NaBH$_4$, HOCH$_2$CH(OH)CH$_2$OH is produced. Which structural formula could X have?
- A1, 2 and 3 are correct
- B1 and 2 only are correct
- C2 and 3 only are correct
- D1 only is correct