Explanation:

Here’s the thing, when people talk about a “social utilitarian” in legal theory, they almost always mean Rudolf von Ihering. Let’s break down the options:

- Ehrlich—He’s known for sociological jurisprudence, focusing on how law actually works in society, not for utilitarian ideas.

- Duguit—His big thing was social solidarity and public service, not utilitarianism per se.

- Ihering —He argued that law’s purpose is social utility—basically, laws should serve society’s needs. That's straight-up social utilitarian thinking.

- None of these—We can skip this; Option 3 is spot on.

So, to sum up: