Fractions in the simplest form essentially means that they cannot be simplified any longer.
5/65 is definitely not in its simplest form since we can divide both the numerator and denominator by their greatest common factor,5, to get a simpler version.
We can divide 2 and 10 by their greatest common factor 2 to get a simpler version, therefore 2/10 isn't the answer.
3/18 can be simplified further as well.
The only thing left is 10/37. 10/37 cannot be simplified further, thusly, that is your answer.
