The answer is: A
Explanation
The correct option is A: A is guilty of extortion as A has put B in fear of injury to his reputation and induced B to give the money.
This is because, according to the principle, extortion requires the intentional putting of any person in fear of any injury and the dishonest inducement of the person so put in fear to deliver any property or valuable security. In this case, A has intentionally put B in fear of injury to his reputation by threatening to publish a defamatory article about him. Reputation is a valuable asset that can be injured by defamation. A has also dishonestly induced B to deliver money, which is a property or valuable security, by making the threat.
Therefore, A has committed the offence of extortion under Section 383 of the Indian Penal Code, 1860.