primary sources of contract law

 Which of the following are the two most important primary sources of contract law?

Case law and the restatement of law
Case law and the Uniform Commercial Code
The Uniform Commercial Code and the Convention on Contracts for International Sales of Goods
Case law and the Convention on Contracts for International Sales of Goods
The Convention on Contracts for International Sales of Goods and the Restatement of the Law Second, Contracts