Which of the following statements about interjections is false?
a. interjections have little grammatical value in a sentence.
b. interjections express strong emotional excitement.
c. interjections are always followed by either an exclamation mark or a comma.
d. interjections are frequently used in professional correspondence.

The statement about interjections which is false is D. interjections are frequently used in professional correspondence. This is false because interjections are a characteristic of informal speech and writing, and thus should be avoided when it comes to formal correspondence. Interjections do not have grammatical value, but rather semantic. They do express strong emotions, exclamations such as God! Hurray!, etc. They are indeed always followed by either an exclamation mark or a comma.