Current Thought Suggests That ADHD Results from Which of the Following

Current thought suggests that ADHD results from which of the following:

A) too much dopamine in the frontal cortex
B) too little dopamine in the basal ganglia region of the brain
C) deficiency or dysfunction of the neurotransmitter dopamine in the regions of the bran that control activity and attention
D) the absence of the neurotransmitter dopamine