Assume That the Delay of Reinforcement Gradient Is Steeper in Children

Assume that the delay of reinforcement gradient is steeper in children with attention-deficit/hyperactivity (ADHD) . Which of the following best explains the symptoms of ADHD?

A) Classroom behaviors have a short interval between behavior and reinforcement.
B) ADHD children are less sensitive to rewards, regardless of the interval between response and reinforcement.
C) Serotonin agonists alter the gradient of reinforcement.
D) Classroom behaviors have a long interval between behavior and reinforcement.
E) Reinforcements that follow a short delay are less effective in ADHD children.