The answer given is (D) but I think (B) should be the answer as the concerned benzylic carbon in option (D) is an unstable tetrahedral complex andand it should break. Besides, the medium is acidic so it should catalyse this process.
OnIn generalising, my question is: are lactols stable?
Edit: I found online that there is an equilibrium between lactols and corresponding hydroxyaldehyde. So, why the lacollactol is favoured more in this case?