Read the following context and choose the best option to answer the question.
Context: I woke up with body and stomach cramps and a mild temperature ... oh oh . So I basically ate nothing and spent the day in bed . It proved the right strategy because 24 hours later I was much improved ! In retrospect I had the virus for a couple of days and the muscle pains were part of what made the bed uncomfortable .
Question: Why is the narrator potentially sore ?
Options: 
A. They are suffering from a bad day .
B. They are suffering from a flu .
C. None of the above choices .
D. They are suffering from a sports injury .


B