Mathew is a sales manager at a local advertising company. Lately, he has been dissatisfied with the performance of his team and assumes this is due to laziness on their part. After looking into the situation closer, he realized he has made a "fundamental attribution error." This means that he has:
A) Only attended to superficial indicators.
B) Inadequately explored the job satisfaction of the salespeople.
C) Merely stereotyped employees.
D) Underestimated the effects of external factors relative to internal factors.
E) Ignored his responsibility in the entire process of not holding workers accountable.