Which of the following is not an example of a rational number? A. 5 B. \( \sqrt[2]{5} \) C. 25 D. \( \sqrt[2]{\frac{1}{25}} \)

To determine which of the options is not a rational number, we need to understand what a rational number is. A rational number is any number that can be expressed as the quotient or fraction \( \frac{p}{q} \), where \( p \) and \( q \) are integers and \( q \neq 0 \). Let's analyze each option: A. \( 5 \) - This is a whole number and can be expressed as \( \frac{5}{1} \). Therefore, it is a rational number. B. \( \sqrt[2]{5} \) - The square root of 5 is an irrational number because it cannot be expressed as a fraction of two integers. Therefore, this is not a rational number. C. \( 25 \) - This is also a whole number and can be expressed as \( \frac{25}{1} \). Therefore, it is a rational number. D. \( \sqrt[2]{\frac{1}{25}} \) - This can be simplified to \( \frac{1}{5} \), which is a rational number since it can be expressed as \( \frac{1}{5} \). Based on this analysis, the option that is not a rational number is: **B. \( \sqrt[2]{5} \)**.