Rational and Irrational Numbers

A number is called rational if it can be written in the form where p and q are integers and q ≠ 0.
2, 7 and 15 are not perfect squares.
So, their square roots will be irrational numbers.
Hence, √2, √7 and √15 are irrational numbers.
25 is a perfect square and √25 can be simplified as √25 = ±5.
Here, both 5 and - 5 are rational numbers.
So, √25 is a rational number.
Therefore, option (d) is correct.