In the Context of International Business Negotiations, Which of the Following

In the context of international business negotiations, which of the following methods is the most efficient way to communicate with clients and partners in places like Mexico, Malaysia, and China?

A) Conversations over long dinners.
B) Negotiations through video-conferencing.
C) Conversations over the telephone.
D) Negotiations through electronic mail.
E) Negotiations between lower- to mid-ranking executives.