单选题 What is the main idea of last two paragraphs?

A、 The difference and resemblance of using language between human beings and animals.
B、 The function of language.
C、 How the human beings produce the sound.
D、 Humans are characterized in many ways to use symbolic communication.

【正确答案】 D

【答案解析】最后两段讲了人类在使用标志方面非常具有自身特点，是其标志之一。故选D。