It did n't get better but worse the next morning , the temperature went up to 40 Celsius and the joints were so pain , could hardly move or walk . Was also feeling cold , though with a winter jacket on in this summary weather . Could n't even drive to see a doctor , had to call dad at work , he was busy and could only leave in the afternoon . My mom cooked some porridge for lunch , though did n't have any appetite , forced half a bowl down the throat .
According to the above context, choose the best option to answer the following question.
Question: What may be the reason why they 're so sick ?
Options:
- They have the flu .
 - They have an infection .
 - They have a disease .
 - None of the above choices .


They have the flu .