First of all take a look what is a terminating decimaL
https://gre.myprepclub.com/forum/gre-ma ... tml#p98026It is difficult to see such question pure on the GRE. However, it is quite good to know how manipulate fraction and see if we do have a terminating or not
Terminating is when the numbers on the right side of zero are in a recursive manner
You do not have no choice but to go through every option and look at the denominator
A. is 91=13*7=non terminating
B. is 225=3^2*5^2= non terminating
C. is 231=7*11= non terminating
D. is 256=2^8 it is terminating
E. is 324=2^2*3^4 non terminating
D is the answer