The number that fits into all the following number sets: natural number, whole number, and integer is 8.
- Natural numbers are the set of positive integers (1, 2, 3, ...).
- Whole numbers are natural numbers including zero (0, 1, 2, 3, ...).
- Integers include all whole numbers and their negative counterparts (..., -3, -2, -1, 0, 1, 2, 3, ...).
The only number from your provided options that is a natural number, whole number, and integer is 8.