Which of the following statements is NOT true?

Which of the following statements is NOT true?

A.According to semanticists, a word is a unit of meaning.

B.According to grammarians, a word is a free form that can function in a sentence.

C.In visual terms , a word can be defined as a meaningful group of letters printed or written horizontally across a piece of paper.

D.In terms of spoken language, a word is viewed as a sound or combination of sounds which are made involuntarily with human vocal equipment.

正确答案是D