To find the difference of given expression:

First step is to subtract the whole number5 and 3.
So, 5 - 3 = 2.
Now we can find the difference of fractions.
To subtract the fractions , we need to find the common denominator.
Common denominator of 3 and 5 is 15.
So, we need to make both the denominator equal to 15.

Similarly,

Therefore,

=

=

So, the difference of given expression is
.
So, the correct choice is C.