Answer:
B) The author is informed and concerned about heatstroke.
Step-by-step explanation:
The author of the passage seems to be well informed about the harms of heatstroke and how it can be prevented. He just knows about the causes of heatstroke, the main victims and how it may be prevented or remedied before things turn fatal.
Since there are no direct references about whether he works with the company that makes the Thermometer Pills, option D can't be the answer. Also, we don't find any indication of him being a medical doctor or a nurse nor is there anything that may show that he knows an athlete who is a victim of heatstroke. So, the correct answer from the options provided will be B) The author is informed and concerned about heatstroke.