Why Is It That Less Is Known About Mathematics Learning

Why is it that less is known about mathematics learning disabilities than reading disabilities?

A) Because the parts of the brain responsible for mathematics skills have not yet been identified, while the areas that control reading are well understood.
B) Because there are very few times when mathematics skills are needed in real life, while reading is something that we do on a continual basis.
C) Because children are given more encouragement to learn to read than to learn math skills.
D) Because mathematics engages a broader set of skills than reading.