An irrational number is a real number that cannot be express...

Question Analysis
This question tests the student's ability to recognize and recall the definition of irrational numbers and provide a common example.

Key Concept Explanation
Irrational numbers are real numbers that cannot be expressed as a ratio of two integers and have non-terminating, non-repeating decimal expansions.

Step-by-step Solution
1. The question asks that what number categories does