Context: As some of you know I have left the Appalachian Trail at Duncannon , Pa. , after having some trouble with my knees and having to get back to work anyway . I had a few pictures left on my digital camera and I felt I should share them , as well as what I plan to do on the Trail next . While I was in Duncannon I actually met Bilge Rat , the occasional hiker and merchant mariner whose favorite thing to do is to play pranks on other hikers . He was responsible for a fake electrical outlet and telephone booth in shelters in North Carolina .

Question: Why did you have some trouble with your knees at the Appalachian trail ?
Options:
0. I had some trouble with my knees at the Appalachian trail my work had me walking all over North Caolina .
1. I had some trouble with my knees at the Appalachian trail because I tripped on the trail while walking with camera .
2. None of the above choices .
3. I had some trouble with my knees at the Appalachian trail because I traveeld across Duncannon , Pa.
Answer: 1