Abraham Has Difficulty in School When Asked to Sit for Long

Abraham has difficulty in school when asked to sit for long periods of time. He frequently gets up and walks around the room, often inadvertently causing a disruption. He does poorly on repetitive tasks, and rarely completes his homework. Abraham most likely has which of the following conditions?

A) Mental retardation
B) Attention deficit/hyperactivity disorder
C) Down syndrome
D) Dyslexia