Answer --  (b) Watson and Crick

Into the biology, The "double helix" is a term used to describe the structure of DNA. Where a DNA double helix consists of two spiral chains of deoxyribonucleic acid. The shape is similar to that of a spiral staircase. DNA is a nucleic acid composed of nitrogenous bases (adenine, cytosine, guanine, and thymine), a five-carbon sugar (deoxyribose), and phosphate molecules. The nucleotide bases of DNA represent the stair steps of the staircase, and the deoxyribose and phosphate molecules form the sides of the staircase.