I Want to Test $H _ { 0 } : p = .4$

Multiple Choice

I want to test $H _ { 0 } : p = .4$ vs. $H _ { \mathrm { a } } : p \neq .4$ using a test of hypothesis. If I concluded that $p$ is $.4$ when, in fact, the true value of $p$ is not $.4$ , then I have made a______

A) Type I error
B) Type II error
C) Type I and Type II error
D) correct decision