Neural tube defect is due to deficiency of -

Ans. is 'a' i.e.. Folate "Folic acid supplementation can reduce the risk of NTDs, presumably by preventing nutritional deficiency and by overcoming disruptions in folate metabolism related to underlying genetic variation in folate-related genes. Folic acid may enhance cell proliferation for neural closure directly or it may be involved in the epigenetic regulation of expression of genes that control neural closure."