Five Year Old Jake Brags to His Two Year Old

Five year old Jake brags to his two year old sister Kayla that his brain is bigger than hers. Jake's mother quickly points out that her brain is even bigger than Jake's. Compared to their mother, what are the relative sizes of Jake's and Kayla's brains?

A) Jake's is 30% smaller; Kayla's is 45% smaller.
B) Jake's is 10% smaller; Kayla's is 45% smaller.
C) Jake's is 30% smaller; Kayla's is 25% smaller.
D) Jake's is 10% smaller; Kayla's is 25% smaller.