【名词&注释】
人民法院(people court)、强制性(compulsory)、买卖合同(sales contract)、行政法规(administrative regulation)、书面形式(written form)、履行抗辩权(defence right of performance)、次债务人(second debtor)、代位权诉讼(lawsuit of right of subrogation)、技术转让合同(technology transfer contract)、行使代位权(exercise his subrogation)
[单选题]下列合同中,应当采取书面形式的是()
A. A.技术转让合同(technology transfer contract)
B. B.买卖合同
C. C.租赁合同
D. D.保管合同