Fractions that are greater than 0 but less than 1 are called proper fractions.
In proper fractions, the numerator is less than the denominator.
When a fraction has a numerator that is greater than or equal to the denominator, then the fraction is an improper fraction.
An improper fraction is always 1 or greater than 1.
Now looking at options
23=.666<1
34=.75<1
57=.71<1
65=1.2>1
So 65 is Not a Proper fraction.
So option D is correct.