Help the detective write her warning accurately! She wants to text her team that only the suspects wearing red hats are dangerous (the suspects in blue hats are totally harmless).

Choose the sentence that expresses this exact meaning.

The correct answer is The suspects who are wearing red hats are highly dangerous.

To specify which suspects are dangerous, you need a defining relative clause, which does NOT use commas. This tells us we are only talking about a specific group of suspects.

The sentence with commas ("The suspects, who are wearing red hats, are highly dangerous.") would mean that all the suspects are wearing red hats, and all of them are dangerous! The options with only one comma are grammatically incorrect because you cannot separate a subject from its verb with a single comma.