The lactone shown is treated with various hydride reagents followed by aqueous work-up. Select ALL correct statements.

AExcess $LiAlH X_{4}$ gives a diol with the two hydroxyl groups on carbons 1 and 4 of a five-carbon chain.
B $DIBAL - H$ (1 equivalent, $- 7 8^{\circ} C$ ) can stop at the lactol (cyclic hemiacetal) stage.
C $NaBH X_{4}$ in methanol at room temperature reduces the lactone rapidly to the diol.
DThe diol obtained with $LiAlH X_{4}$ contains one stereocentre.

Answer: A, B, D

The compound is gamma-valerolactone. Excess

LiAlH X_{4}

opens the ring and reduces the acyl carbon to

CH X_{2} OH

, giving pentane-1,4-diol (true), which has one stereocentre at C4 (true). With one equivalent of DIBAL-H at

- 7 8^{\circ} C

the reduction stops at the lactol (true).

NaBH X_{4}

does not reduce simple lactones/esters at room temperature, so statement 3 is false.