Context: After a couple weeks on our mountain bike vacation , we 're home . We had to cut it a day short because my right leg started hurting again ... seems to be a muscle strain again . I 'll get to the details of that in a few days .

Question: Why did she strain her muscle on her mountain bike vacation ?
Options:
0. She strained her muscle on the alpine ski slope .
1. The muscle was strained before she took the trip .
2. She biked for too many days straight .
3. None of the above choices .
Answer: 2