To solve this problem, we need to match the scientists with their correct contributions or discoveries. Let's analyze each option:$\newline \bullet$Option 1: Meselson and Stahl - Pisum sativum$\newline$ - Meselson and Stahl are known for their experiment demonstrating the semi-conservative replication of DNA, not related to Pisum sativum (pea plant).$\newline$ - Pisum sativum is associated with Gregor Mendel's experiments on inheritance.$\newline$ - Therefore, this match is incorrect.$\newline \bullet$Option 2: Hershey and Chase - TMV$\newline$ - Hershey and Chase conducted experiments with bacteriophages to show that DNA is the genetic material, not related to TMV (Tobacco Mosaic Virus).$\newline$ - TMV is associated with the work of Wendell Stanley.$\newline$ - Therefore, this match is incorrect.$\newline \bullet$Option 3: Alec Jeffreys - Streptococcus pneumoniae$\newline$ - Alec Jeffreys is known for developing DNA fingerprinting, not related to Streptococcus pneumoniae.$\newline$ - Streptococcus pneumoniae is associated with Frederick Griffith's experiment on transformation.$\newline$ - Therefore, this match is incorrect.$\newline \bullet$Option 4: Jacob and Monod - Lac operon$\newline$ - Jacob and Monod are known for their work on the lac operon, which is a model for gene regulation in prokaryotes.$\newline$ - This match is correct.$\newline$Therefore, the correct match is:$\newline$Option 4: Jacob and Monod - Lac operon$\newline$This corresponds to the correct option, which is Option 4.