Percent of Category A cases = 33.7% ≈ 34%
Percent of Category B cases = 39.8% ≈ 40%
Percent of Category C cases = 100% – (34 + 40) = 26%
It is better to divide each of the piecharts into 4 quarters to give you an idea of there 25%, 50%, 75% and 100% are. You can easily do this using a ruler or a pencil.
Category C is the lowest. Therefore, we can easily eliminate A and B.
C is little bit confusing but we can see that the portion of Category A and C are roughly the same. Hence, C is wrong. as different between A and C is 8%
D is correct by process of elimination.