In this reaction : $CH_3CHO + HCN \to CH_3CH(OHCN) \overset{H.OH}{\rightarrow} CH_3CH(OH)COOH$ an asymmetric centre is generated. The acid obtained would be :

Question

( A ) D- isomer
( B ) 20% D+80% L- isomer
( C ) 50% D + 50% L-isomer
( D ) L- isomer