49. Which of the following statements is TRUE of non-verbal communication? __________
选项：

A:
A: Non-verbal communication serves a variety of purposes.;
B:
B: Non-verbal communication is less important than verbal communication.;
C:
C: Since non-verbal communication is hard to interpret, it is important to reduce it to the minimum in cross-cultural communication.;
D:
D: Non-verbal communication is not effective without verbal communication.