Which one of the following regular expressions is equivalent to the language accepted by the DFA given below?

Let M be the 5-state NFA with ε-transitions shown in the diagram below.

Which one of the following regular expressions represents the language accepted by M?

Consider a context-free grammar $G$ with the following 3 rules.

$S \rightarrow aS, \ S \rightarrow aSbS, S \rightarrow c$

Let $w \in L(G)$.

Let $n_a(w)$, $n_b(w)$, $n_c(w)$ denote the number of times $a$, $b$, $c$ occur in $w$, respectively. Which of the following statements is/are TRUE?

Let L₁ be the language represented by the regular expression b^*ab^*(ab^*ab^*)^* and L₂ = { w ∈ (a + b)^* | |w| ≤ 4 }, where |w| denotes the length of string w. The number of strings in L₂ which are also in L₁ is __________.