The set of numbers that are real numbers but cannot be expressed as one integer divided by another are known as irrational numbers.
Rational numbers can be expressed as the quotient of two integers (where the denominator is not zero), while irrational numbers cannot be expressed in this way. Examples of irrational numbers include \(\sqrt{2}\), \(\pi\), and \(e\).
So the correct option from your list is: irrational.