Brandon Has Difficulty Sitting Still in Class

Brandon has difficulty sitting still in class. He fidgets a lot, is easily distracted, and often draws the attention of his teacher when she's trying to teach a lesson. He is not intentionally problematic, but the issue has required the teacher to contact his parents on several occasions. Brandon is experiencing symptoms consistent with which disorder?

A) conduct disorder
B) attention-deficit/hyperactivity disorder
C) oppositional-defiant disorder
D) separation anxiety disorder