Watson and Crick proposed what structure of DNA based on data from other researchers?

Watson and Crick proposed the double helical structure of DNA based on a combination of experimental data gathered from other researchers, most notably Rosalind Franklin's X-ray diffraction images and Chargaff's rules regarding base pairing. Their model described DNA as a double-stranded helix, where two strands run in opposite directions and are held together by complementary base pairing (adenine with thymine and guanine with cytosine). This structure explained how genetic information could be stored and replicated accurately. The double helix also provided insights into the stability and functionality of DNA, which became foundational for understanding genetics and molecular biology. The other options do not reflect the correct structure that Watson and Crick described, as they all misrepresent the nature of DNA as understood from the available evidence.