Ethyl 3-oxobutanoate, $\mathrm{CH}{}_3\mathrm{COCH}{}_2\mathrm{COOC}{}_2\mathrm{H}{}_5$, is treated with different reducing agents under the stated conditions. Which statements are correct?

1. A$\mathrm{NaBH}{}_4$ in ethanol at 0 ${}^{\circ }\mathrm{C}$ gives ethyl 3-hydroxybutanoate
2. BExcess $\mathrm{LiAlH}{}_4$ in dry ether, followed by aqueous work-up, gives butane-1,3-diol
3. C$\mathrm{NaBH}{}_4$ in ethanol at 0 ${}^{\circ }\mathrm{C}$ gives butane-1,3-diol
4. D$\mathrm{N}{}_2\mathrm{H}{}_4$, hot $\mathrm{KOH}$ in ethylene glycol leaves the ester group unchanged