What should come in place of the question mark (?) in the given series based on the English alphabetical order?
XPR, UMO, RJL, OGI, ?

Given: XPR, UMO, RJL, OGI, ?

Logic: Letters are decreasing - 3 place.

X - 3 = U, U - 3 = R, R - 3 = O, O - 3 = L

P - 3 = M, M - 3 = J, J - 3 = G, G - 3 = D

R - 3 = O, O - 3 = L, L - 3 = I, I - 3 = F

So, the missing term is LDF.

Thus, correct option is (a).