Four Students Have Suppressed Math Computation Scores

Four students have suppressed math computation scores.Which one of the following has a learning disability?

A) John has average scores in all other academic areas and tested in the average range of intellectual ability.
B) Sandra is visually impaired and struggles to see the chalkboard from where she sits.
C) Alex is hearing impaired and frequently misses key details in instruction.
D) Janet is diagnosed with bipolar disorder.Her behavior impedes her ability to access the general curriculum.