Answer:
The correct answer is letter "A": looking for loopholes in patent protection and exploiting them.
Step-by-step explanation:
Patent trolling is the act by which a company looks for structural issues in the patent and court systems so the firm files court cases to earn revenue. There is no need from the filing company to be engaged in the development of an item related to the patent claimed as vague.
Patent trolling is not considered an illegal activity in the U.S.