Context: Wow ... as they say , " When it rains it pours . " Our auxiliary backup emergency dog Remy passed away this morning . She was 13 . She was not feeling well and we took her to the vet yesterday . For some unknown reason , her red blood cells were attacking each other .
Question: What may be the reason that Remy ’s red blood cells start attacking each other ?
Option 0: She was not feeling well .
Option 1: The reason is entirely unknown .
Option 2: None of the above choices .
Option 3: She was already 13 years old .
Answer: 1