Which of the following statements is NOT true of the passage

A．International trade has become an important part of national development.

B．Summit talks will be held to discuss problems in international trade.

C．Developing countries benefit more from international trade than development aid.

D．The Doha Development Agenda has made development its pivotal concern.

1980年《国际货物买卖合同公约》第15条第1款规定，发价于其（）时生效。