Answer:
D. Sqroot6
Explanation:
6 is not a perfect square. So it is a non-repeating decimal that never ends
sqroot6 ~=
2.4494897428...
this is an irrational number.
The rest on the numbers can be written as a ratio:
0.45=45/100=9/20
0.63636363
= 63/99 = 7/11
sqrt25 = 5 = 5/1
that means they are rational.