Let $N_f$ and $N_p$ denote the classes of languages accepted by non-deterministic finite automata and non-deterministic push-down automata, respectively. Let $D_f$ and $D_p$ denote the classes of languages accepted by deterministic finite automata and deterministic push-down automata respectively. Which one of the following is TRUE?
$D_f \subset N_f \text{ and } D_p \subset N_p$
$D_f \subset N_f \text{ and } D_p = N_p$
$D_f = N_f \text{ and } D_p = N_p$
$D_f =N_f \text{ and } D_p \subset N_p$
Gatecse