Problem: Audrey is a personal trainer taking her client through the ventilatory threshold 1 (VT1) test. Which option indicates that her client has reached VT1? Select one: a. After completing the talk test, Audrey's client's speech and breathing rates have not noticeably changed, and she can speak in complete sentences. b. After completing the talk test, Audrey's client's speech has become challenging, and her breathing has become clearly audible with fairly visible signs of rib cage elevation. c. After completing the talk test, Audrey's client's speech has become choppy, and she can only speak with short one-word answers and displays labored breathing. d. After completing the talk test, Audrey's client's speech has become disjointed, and she can no longer communicate except for grunting or nodding her head.