Which of the following statements is INCORRECT about the Speech Act Theory

[A] The main idea of the theory is that things can be done with words.
B. This is the first major theory in the study of language in use.
C. There are two types of sentences according to this theory: performatives and constatives.
D. As a sense of this theory, Illocutionary Act refers to the result or effects that are produced by meanings of saying something.