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.



None of them is true; the explanation is here:
- F: They can be still active at the same time, since the cat can alternate between sleeping and being awake, both each hour; meaning at night, it's possible that hamster and cat be active simultaneously.
- G: Same explanation with F, just that it is day that cat can do be active.
- H: The hamster and dog have different times when they wake up, so two of them are active, along with the cat.
- J: Only two of them can be active.
- K: There are exactly two animals that can be active; night and day.