; and (B) such person is a sole source supplier of the product or service, the product or service is not available from any alternative reliable supplier, and the need for the product or service cannot be met in a timely manner by improved manufacturing processes or technological developments. (6) Exceptions The President shall not apply the sanction under this subsection prohibiting the importation of the products of a foreign person— (A) in the case of procurement of defense articles or defense services— (i) under existing contracts or subcontracts, including the exercise of options for production quantities to satisfy requirements essential to the national security of the United States; (ii) if the President determines that the person to which the sanctions would be applied is a sole source supplier of the defense articles or defense services, that the defense articles or defense services are essential to the national security of the United States, and that alternative sources are not readily or reasonably available; or (iii) if the President determines that such articles or services are essential to the national security of the United States under defense coproduction agreements or NATO Programs of Cooperation; (B) to products or services provided under contracts entered into before the date on which the President publishes his intention to impose the sanctions; or (C) to— (i) spare parts; (ii) component parts, but not finished products, essential to United States products or production; (iii) routine services and maintenance of products, to the extent that alternative sources are not readily or reasonably available; or (iv) information and technology essential to United States products or production. (c) Definitions In this section: (1) Appropriate congressional committees The term appropriate congressional committees means— (A) the Committee on Foreign Affairs of the House of Representatives