A\(\sqrt{1}\) equals 1 and that is a rational number
B. \(\sqrt{1} \sqrt{9}\) equals 1*3 = 3 and is a rational number
C.\(\sqrt{25}\) equals 5 and is a rational number
D. \(\sqrt{50}\) equals 7.07106781187. The number doesn't terminate and so it is irrational.
The answer is D
