AMC 12 2019b Problem 2

Consider the statement, "If $n$ is not prime, then $n-2$ is prime." Which of the following values of $n$ is a counterexample to this statement?

$\textbf{(A) } 11 \textbf{(B) } 15 \textbf{(C) } 19 \textbf{(D) } 21 \textbf{(E) } 27$