The third option is also making a generalization.
If a reader can't determine the "how" or "why" from your thesis statement, your thesis might be too open-ended, and you may need to revise it to be more specific or to clarify your point of view.
Doing so tells readers that you understand the topic and have performed some research, which gives you more credibility as a persuasive writer. You'd have to find that, factually, every person who has ever eaten potato chips has broken out because of that direct link.
Does her brother like broccoli? The fourth option is once again easy enough to verify.
But is it a fact that all cops love doughnuts? The third option is verifiable enough. An easy way to test your thesis is to ask yourself whether your reader could challenge or oppose your thesis statement. And on the topic of generalization, question 3.
Can you verify triple cheeseburgers have a high caloric count?