Here's the Question:

Which Rx has the most vertical imbalance at reading level of 10mm below distance optical center:

a, +2.00-0.50x90 b, -3.75-1.00x180 c, -6.50-2.25x90
-1.50+0.50x180 +0.75+0.50x180 -1.50-1.75x90

d, +8.25+1.50x90
+3.50+1.00x180

--- The answer was B, but i got C. I cant figure out how can it be? can u help me? THANKS..