A whole number is a non-negative integer, which includes all natural numbers (1, 2, 3, ...) and the number 0. Natural numbers start from 1 and go upward (1, 2, 3, ...).
Out of the options provided:
- 0 is a whole number but not a natural number.
- -12 is neither a whole number nor a natural number.
- 22 and 3 are both natural numbers.
Therefore, the answer is 0.