The correct option is D gala
It is given that 'acme' is to 'mace'. The 3rd letter is shifted to the 1st position, the 1st letter is shift to 2nd position, 2nd letter is shifted to the 3rd position and the 4th letter is kept unchanged at the 4th position. Thus, 'alga' can be repositioned as 'gala'. Hence, the correct option is D.