Thanks for the question! Let’s say that J isn’t included in the display. That means out of the kittens, we can pick F and G/H (rule 3). We know that we can’t only pick one kitten, since the first and fifth pens both have kittens, so we’re going to pick 2 kittens and 3 dogs.
We know that the kittens will be in the first and last pens (rule 1). We can thus eliminate (A), since that’s a case of a kitten not in one of those pens.
Now, out of the puppies, we know we can’t pick W, since that would pick a kitten (G) in pen 2; this lets us eliminate (E). So we know that the puppies we pick will be R, S, and T, and we know that T is in the third pen because of rule 2, allowing us to eliminate (C) and (D). By process of elimination, we know that the correct answer is (B). Indeed,
F R/S T S/R H
complies with the hypothetical and the rules of the game.
Hope this helps! Feel free to ask any other questions that you might have.
