Context: Apparently I ' m very allergic to cats . Did n't know that exactly until just these past two weeks . I fell asleep on the couch in the living room two weekends ago and had terrible sinus reactions . But here 's the rub .

Question: Why did falling asleep on the couch and becoming ill lead the speaker to realize they must be allergic to cats ?
Options:
0. None of the above choices .
1. The cat was confused at the fact of them sleeping on the couch and proceeded to scratch them
2. The cat had peed on the couch to try to mark it 's territory and this is what the speaker was allergic to
3. The couch is where the cats frequently reside and as a result it is covered in their fur
Answer: 3

Question: Why did falling asleep on the couch and becoming ill lead the speaker to realize they must be allergic to cats ?
Options:
0. The cat had peed on the couch to try to mark it 's territory and this is what the speaker was allergic to
1. The cat hair is very prevalent on furniture in the speaker 's house , and the couch is one example
2. None of the above choices .
3. The cat was confused at the fact of them sleeping on the couch and proceeded to scratch them
Answer: 1