According to the teacher, why is code-switching（here it refers to a mix-use of formal and informal registers）popular in academic presentations?

A.It can make the audience feel that your academic presentation is very professional.

B.It can make your presentation easier to be understood.

C.It can create contrast and add more variety to the language one uses in the academic presentation.

D.It can allow the speaker to transmit more information in a limited time period.

正确答案：It can create contrast and add more variety to the language one uses in the academic presentation.