Which of the following expresses a correct principle of law?

• A. Failure to disclose facts when there is a duty to reveal them, does not constitute fraud.
• B. Violence or intimidation does not render a contract annullable if employed not by a contracting party but by a third person.
• C. A threat to enforce one s claim through competent authority, if the claim is legal or just, does not vitiate consent.
• D. Simulation of a contract always results in a void contract.