The five kingdoms in which living creatures are divided are: animal, plant, fungi, protist and monera. Observing each alternative, we can say that grass (plant), worm (animal) and shark (animal) aren't from the same kingdom. Therefore, B is wrong. Mold (fungi), bacteria (monera) and apple tree (plants) aren't from the same kingdom as well. Therefore, C is also wrong. Fern (plant), mushroom (fungi) and corn plant (plant) aren't from the same kingdom too. Therefore, D is incorrect as well. But, cat (animal), frog (animal) and cockroach (animal) are all members of the same kingdom, as they're all animals. Therefore, the correct answer is A. cat, frog and cockroach.