A real number is a value that represents a quantity along a line. Real numbers include all rational numbers. -23 is a real number.
A rational number is any number that is not complex or imaginary. -23 is a rational number.
An irrational number is a real number that cannot be written as a simple fraction. Irrational means not rational. -23 is not an irrational number.
An integer is a whole number that can be positive, negative, or zero. -23 is a rational number.
A natural number is a positive integer. -23 is not a natural number.
A whole number is one of the positive integers or zero. -23 is not a whole number.
Because of the above, the answer is a / option 1.