Complete the letter analogy: DG : CI :: LO : ?

The first letter moves one place back while the second moves two places forward: D − 1 = C and G + 2 = I. Doing the same to LO gives L − 1 = K and O + 2 = Q, so KQ. MQ moves the first letter forward instead of back, KR pushes the second letter three places instead of two, and JQ takes the first letter two places back instead of one.