I believe the answer to your question is GUILT. Its the only one that makes sense.
Positive, exercise helps your respiratory and circulatory systems get stronger.
The best and most correct answer among the choices provided by the question is the first choice "flu"
The flu<span> is an acute respiratory illness caused by </span>influenza<span> viruses A or B . Most people who get the </span>flu<span> recover completely in 1 to 2 weeks, but some people develop serious and potentially life-threatening medical complications, such as pneumonia.</span>
I hope my answer has come to your help. God bless and have a nice day ahead!