The correct answer is A) Eating lunch outside can provide many health benefits for students.
Step-by-step explanation:
An effective claim should be an arguable position or perspective about an issue, this means the claim should not only report a fact but a perspective and this should be supported by evidence, reasons, etc. to be valid.
According to this, the option that is a claim is option A because this shows a specific position about eating lunch outside as the author claims this "can provide many health benefits for students"; also, this is the only option that is supported by other as facts such as it provides vitamin D (option C), reduces stress (Option D), etc. prove and explain the benefits the author claims.