Are the square roots of all positive integers irrational? If not,give an example of the square root of a number that is a rational number.

(B) No,the square roots of all positive integers are not irrational.
For example,consider the square roots of perfect squares such as $\sqrt{4}$ and $\sqrt{9}$.
We know that $\sqrt{4} = 2$ and $\sqrt{9} = 3$.
Since $2$ and $3$ can be expressed in the form $\frac{p}{q}$ (where $p$ and $q$ are integers and $q \neq 0$),they are rational numbers.
Therefore,the square roots of all positive integers are not irrational.