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