The correct option is D Watson and Crick
Watson-Crick Structure of DNA is a double-stranded, helical molecule consisting of two sugar-phosphate backbones on the outside, held together by hydrogen bonds between pairs of nitrogenous bases on the inside. In the paper "A Structure for Deoxyribose Nucleic Acid." written by j.D.Watson and F.H.C. Crick, they proposed the double helix structure of DNA. Further, in the paper, they expressed the exciting aspect of specific pairing as the key aspect of the structure in their own words-"It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for genetic material".