Question:
Which of the following is a rational number?
(a) $\sqrt{5}$
(b) $0.101001000100001 \ldots$
(c) $\pi$
(d) $0.853853853 \ldots$
Solution:
Since, a number whose decimal expansion is terminating or non-terminating recurring is rational number.
So, 0.853853853... is a rational number.
Hence, the correct option is (d).