Which of the following statements are not nonsense?

Choice $1$ of $3$: $A_{\text{D}\text{F}\text{A}}$is decidable

Choice $2$ of $3$: If D is a DFA, the string $($D$)$ is decidable

Choice $3$ of $3$: $M_{A_{\text{D}\text{F}\text{A}}}$is decidable