Can someone please explain (with some detail if possible) why (C) is the correct answer. Thanks.

Correct the imbalance in the following prescription by use of “slab off” (10mm reading depth) how much slab-off and in which eye?


+5.00 -2.00 x90
+3.37 -3.00 x90


(A) 1.20 BU in OD
(B) 1.20 BU in OS
(C) 1.60 BU in OS
(D) 1.60 BU in OD