Answer:
The coach should suspect that the runner might be taking anabolic steroids.
Step-by-step explanation:
Anabolic steroids may even improve an athlete's performance, but they promote rapid fatigue, increased aggression, sudden mood swings, and even depressive or paranoid states can be noticed. The athlete shown in the above question shows an improvement in his performance but gets tired quickly and looks depressed. These are signs of the use of anabolic steroids and should be noted by the trainer, who must take action towards the athlete.