So the first thing you do is to figure out what E(26) is actually equal to. To do that, just plug in 26 for n in the first equation. Doing so, you get,
E(26) = 2 * 26 = 52
Now using that, you can determine that A is equal and B is not.
For C and D it is a little more complicated. For C, all you have to do is figure out what E(13) is, by the method we used to find E(26), and add 13.
For D, you have to figure out both E(20) and E(6) then add them together.
