The Letter Which Best Completes The Sequence Below Is: Y S N J G?

I believe it's E.
The number of letters between each letter in the series decreases by one each time, in reverse alphabetical order.
Y(XWVUT)S = 5 letter interval
S(RQPO)N = 4 letters
N(MLK)J = 3 letters
J(IH)G = 2 letters
So I'd say:
G(F)E = 1 letter