The answer is A.
What you can do is distribute the 1/4 or 4 into the parentheses and see if it is the expression you want:
[tex] \frac{1}{4}(n-64)\\ \frac{1}{4}n-(\frac{64}{4})\\\frac{1}{4}n-16\\\\4(n-4)\\4n-16\\\\4(n-64)\\4n-(4*64)\\4n-256[/tex]
Since only option A simplifies to [tex] \frac{1}{4}n-16 [/tex], A is your answer.