单项选择题

Science Citation Index-Expanded(SCI-E)数据库中,课题“两性聚电解质溶液的结构研究”,最佳检索式为:()

A.ts="study on the structure of polyampholyte solution"
B.ts=structure and ts="polyampholyte solution"
C.ts=structure or ts=polyampholyte solution
D.ts=structure and ts=polyampholyte solution