How long was it from the time when China applied to join GATT till the deal between the US and China was signed

A．The flight number.
B．The gate number.
C．The arrival time.
D．The airplane.

A．A professor in university.
B．A member of the negotiating group.
C．An official of the Ministry of Foreign Trade and Economic Co-operation.
D．An official of the State Economic and Trade Commission.