A 67-year-old female presents to clinic with complaints of numbness and tingling in her left foot ongoing for 1 week. The patient does not recall any inciting events nor has she observed any aggravating or alleviating factors. Further questioning reveals that the patient has had chronic low back pain. Vitals are within normal limits. Physical examination reveals decreased sensation at the lateral malleolus. Which of the following nerve roots is mostly responsible for the Achilles reflex?