Explanation

Photo 51 is the famous X-ray diffraction image of crystallised DNA taken by Rosalind Franklin and Raymond Gosling at King's College London in 1952. Its distinctive X-shaped pattern revealed the double-helix structure and was crucial to Watson and Crick's model of DNA. It is not an image of a lunar crater or any virus. The answer is (B). (Cross-checked with Testbook's CDS-I 2024 solutions.)