When we have a justifying principle question, "too strong" is not an issue. We want to be as strong as possible! Our job is to guarantee that the conclusion follows, or support it as much as we can. Note the phrase "if valid" in the question stem. This gives the license to be strong. This is like seeing "if true," on a strengthen question. We don't need to worry if it is valid or not. If it strengthens the argument, it is the correct answer.