The most likely number of cats = 21/37 x 8 = 4.54 ≈ 5 cats
The most likely number of dogs = 16/37 x 8 = 3.46 ≈ 3 dogs
The probability of that arrangement happening = 1/8^2 = 1/64 = 0.00156
0.47 is the answer. Because it's in the middle of 0.43 and 0.50. I answered this on your last question =p