Semiessential amino acid -: (A) Alanine, (B) Valine, (C) Histidine, (D) Tyrosine
Answer is C. Essential amino acids inclide leucine,isoleucine,lysine,methionine,phenylalanine,threonine,valine,tryptophan.Histidine is an essential amino acid.(Ref.PARK'S textbook of social and preventive medicine 21st edition page no.562)