Explanation:

- The statement "He has taken functionalism to its logical conclusion" refers to the sociologist who most systematically developed and extended the theory of functionalism.

- Option 1: Durkheim – Emile Durkheim is known as the founding figure of functionalism, exploring how society's parts function together.

- Option 2: Parsons – Talcott Parsons built on Durkheim, formulating a comprehensive system and is often credited with taking functionalism to its logical conclusion.

- Option 3: Merton – Robert K. Merton refined functionalism by introducing concepts like manifest and latent functions, but he did not take it to its logical conclusion.

- Option 4: Weber – Max Weber is known for interpretive sociology and is not linked with functionalism.