Q9

Consider the following definition of a lexical token $\textbf{id}$ for an identifier in a programming language, using extended regular expressions:

$$\begin{array}{ll} \textbf{ letter } & \rightarrow[\mathrm{A}-\mathrm{Za}-\mathrm{z}] \\ \textbf{ digit } & \rightarrow[0-9] \\ \textbf{ id } & \rightarrow \textbf{ letter }(\textbf{ letter } \mid \textbf{ digit })^{*} \end{array}$$

Which one of the following Non-deterministic Finite-state Automata with $\epsilon$-transitions accepts the set of valid identifiers? (A double-circle denotes a final state)