Explanation:

- Roscoe Pound (Option 3) gets the green tick. He’s widely recognized as the American leader in Sociological Jurisprudence. Pound argued law shouldn’t be a rigid set of rules, but a tool to balance competing interests and promote social order. He brought a fresh, people-centered perspective to American law.

- Ihering (Option 1) was a German jurist. He did a ton for sociological theory in Europe, but not American jurisprudence.

- Ehrlich (Option 2) (note the spelling!) came from Austria and was a key figure in the sociology of law, but—again—not American.

- Duguit (Option 4) was French, with big ideas about social solidarity and public service, but his impact was in Europe.

So, Roscoe Pound is your guy. Everyone else on that list was important—just not the American face of sociological jurisprudence.