D). This led to his first patent and a sizable financial reward while still in high school.
Explanation:
As per the question, the last option displays a fact instead of an opinion as it involves the description of an information('first patent and a sizable financial reward') that is compatible with the objective reality and possesses the ability to be verified or proved as true using evidences. The information about 'first patent or the financial award' could be verified to be true by using the past records of Dean Kamen's achievements as evidence. Thus, option D is the correct answer.