How Did Rosalind Franklin Contribute to Our Understanding of DNA

How did Rosalind Franklin contribute to our understanding of DNA?

A) used X-ray diffraction to show that the structure of DNA is helical
B) determined that DNA contains four different nitrogenous bases
C) found that "the transforming principle" is destroyed by enzymes that hydrolyze DNA
D) found that the phosphorus-containing components are the genetic material of phages
E) used models to show that DNA is a double helix