The argument isn't about whether cocker spaniels tend to stray more than other dogs. Regardless of whether they stray more or less, if Flynn Heights actually owns more cocker spaniels than all the other neighborhoods of the city, there is a high likelihood that a stray cocker spaniel found near Flynn Heights would belong to a Flynn Heights resident. This answer choice is irrelevant.

We don’t care about other dog breeds registered within Flynn Heights. Even if residents of Flynn Heights simply had a lot of dogs, generally, as long as they still had more cocker spaniels than the rest of the city, the conclusion of the argument would still follow.

The frequency of finding strays near Flynn Heights isn't relevant. Regardless of how often or rarely strays are found there, we just want to know the likelihood that, once a stray is found there, and it is a cocker spaniel, it belongs to someone in Flynn Heights.

Irrelevant. The argument is focused on cocker spaniels alone. Flynn Heights could still have more cocker spaniels than all other neighborhoods combined, regardless of however many or few other pets lived in Flynn Heights. So this doesn't affect the argument.

This is crucial to evaluating the argument. The argument assumes that because the licensing records show more cocker spaniels registered to Flynn Heights than all other neighborhoods combined, Flynn Heights actually has more cocker spaniels than other neighborhoods. But if Flynn Heights residents are just more likely to license their dogs, then it's possible other neighborhoods have just as many cocker spaniels as Flynn Heights, and just haven't licensed them. This would call the conclusion of the argument into doubt.