The enantiomer in the below reaction is the predominant product of the enantio-selective transformation, it is extremely unlikely that 100% enantiomeric excess would be observed in the product. There are several ways in which the "incorrect" enantiomer of ethyl 3-hydroxybutyrate might form as a miner side-product in this reaction. Based on this, propose two possible explanations for the formation of the other enantiomer of the product. Feel free to use a drawing/diagram, written answer or a combination of both to explain.

Na BHy "L- Ta B Catalyst Trcansition stali OH ethyl 3- tycbuony butyonaty [Single enautiomer)