Let's name the digit:
x- ones digit
y - tens digit
we know that x=y-2.
Now, y can be 6,7,8,9 (the number is between 60 and 100 (so depending on your understanding of "between", 0 is also possible. but then the number would have to have -2 as its ones digit, so in any case, it's not possible).
So the possibilities with x=y-2:
64
75
86
97
Out of those 64 and 86 are even, so they can't be prime.
75 has 5 in its ones number: it's divisible by 5.
so the correct answer is 97.
