The answer is d. tort law
Contract law governs agreements between parties and the enforcement of those agreements. While liability insurance involves contracts, the core principle of liability insurance is to cover the insured against claims arising from their legal liabilities, which is more closely related to tort law.
Criminal law deals with offenses against the state or public, and it involves prosecution by the government. Liability insurance does not typically cover criminal acts, as it is designed to address civil liabilities.
International law governs the relationships between countries and is not directly related to the principles of liability insurance, which is more concerned with domestic legal issues.
Tort law deals with civil wrongs and damages. Liability insurance is primarily concerned with providing coverage for claims arising from torts, such as negligence, defamation, or other civil wrongs that result in harm or loss to another party. Therefore, tort law is the most relevant area of law for liability insurance.