Whose experiments cracked the genetic code and discovered unequivocally that genetic code is triplet
The Nirenberg and Matthaei experiment was a scientific experiment performed in May 1961 by Marshall W. Nirenberg and his post-doctoral fellow, J. Heinrich Matthaei at the National Institutes of Health (NIH). The experiment deciphered the first of the 64 triplet codons in the genetic code by using nucleic acid homopolymers to translate specific amino acids.In the experiment, an extract from bacterial cells that could make protein even when no intact living cells were present was prepared. Adding to this extract an artificial form of RNA consisting entirely of uracil-containing nucleotides (polyuridylic acid or poly-U), caused it to make a protein composed entirely of the amino acid phenylalanine. This experiment cracked the first codon of the genetic code and showed that RNA controlled the production of specific types of protein.
So,the correct option is 'A'.