Javon has three pets at home: a hamster, which is active only at night; a dog, which is active only during the day; and a cat, which alternately sleeps for an hour and then is active for an hour.
Based only on the information above, which of the following must be true?
F. The hamster and the cat will never be active at the same time.
G. The dog and the cat will never be active at the same time.
H. There are times when none of the pets is active.
J. All three animals are active at alternate hours.
K. There never will be more than two pets active at the same time.