Answer:
All.
Step-by-step explanation:
Integers are "colloquially defined as a number that can be written without a fractional component."
Whole numbers are positive integers.
Rational numbers are "a number that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q. Since q may be equal to 1, every integer is a rational number."
The number 15 fits in all of these categories.
