The answer would be
C) 0.7
Step-by-step explanation:
A rational number is a number that can be expressed as an integer or a quotient of two integers.
When it's in decimal form it is usually determined by whether it terminates or repeats.
In this case, 0.7 is the only one that terminates.
A is automatically out since it's visible that it doesn't terminate or repeat.
When B is turned into a decimal it equals 2.23... making it a non-terminating decimal.
Pi is a number that mathematicians haven't even found an end to yet, so answer choice D is out.