Answer: B
Single-source procurement, also known as direct procurement, is a non-competitive procurement method, that is, the procurement agency only purchases from one supplier. Article 31 of the "Government Procurement Law" stipulates the circumstances in which single-source procurement is adopted: (1) Procurement can only be made from the only supplier; (2) Unforeseen emergencies occur and procurement cannot be made from other suppliers; (3) It is necessary to ensure the consistency of the original procurement items or the requirements for supporting services, and it is necessary to continue to purchase additional items from the original supplier, and the total amount of additional purchase funds does not exceed 10% of the original contract purchase amount. Among them, patented technology is a situation that can only be purchased from a single supplier, so the answer is B.