To solve this problem, we need to match the scientists in List I with their corresponding discoveries or models in List II. Let's analyze each scientist:$\newline \bullet$A. Frederick Griffith:$\newline$ - Frederick Griffith is known for his experiment demonstrating the phenomenon of transformation in bacteria.$\newline$ - This matches with III.$\newline \bullet$B. Francis Jacob & Jacque Monod:$\newline$ - They are famous for their work on the lac operon, which is a model for gene regulation in prokaryotes.$\newline$ - This matches with IV.$\newline \bullet$C. Har Gobind Khorana:$\newline$ - Har Gobind Khorana played a significant role in deciphering the genetic code.$\newline$ - This matches with I.$\newline \bullet$D. Meselson & Stahl:$\newline$ - They are known for their experiment that provided evidence for the semi-conservative model of DNA replication.$\newline$ - This matches with II.$\newline$Now, let's match the items from List I with List II:$\newline A \rightarrow III, B \rightarrow IV, C \rightarrow I, D \rightarrow II \newline$This corresponds to Option 4.