— Mary didn't come to school, did she?

— _____ She was ill in bed.[ ]

A. No, she did.

B. Yes, she did.

C. No, she didn't.

D. Yes, she didn't

根据《UCP600》的规定，即使信用证没有规定单据需要签字，出单人也必须签字的单据包括（）。

A．商业发票

B．保险单

C．受益人证明

D．海运提单