The answer is D.
Don't be fooled sqrt(10) goes on for many many places and if you know the 20th digit is a 9 you have a 1 in 10 chance of predicting what the next digit is. The same is true for pi and sqrt(2). The sqrt root of 16 is 4 which is rational. It could be - 4 which is still rational. The other 3 go on forever and each one has the property of unpredictability of the next digit if you know the current digit.
