Which of these is a colony of polyps and not a jellyfish?

The story behind the answer

Portuguese Man-of-War is correct because it isn’t a single animal like a true jellyfish; it’s a siphonophore—a floating colony of specialized polyps (zooids) that function together as one. It has a gas-filled “sail” (pneumatophore) and long, venomous tentacles, but each part is an individual polyp adapted for tasks like floating, feeding, or reproduction. In contrast, Sea Wasp, Irukandji, and Sea