For the grammar below, a partial LL(1) parsing table is also presented along with the grammar. Entries that need to be filled are indicated as E1, E2, and E3. $\varepsilon$ is the empty string, $\$$ indicates end of input, and $\mid$ separates alternate right hand sides of productions. $S \rightarrow aAbB \mid bAaB \mid \varepsilon$ $A \rightarrow S$ $B \rightarrow S$ The FIRST and FOLLOW sets for the non-terminals A and B are

To compute $\text{FIRST}$ and $\text{FOLLOW}$ sets:

1. FIRST Sets:

   • From $S \rightarrow aAbB \mid bAaB \mid \varepsilon$, we have $\text{FIRST}(S) = \{a, b, \varepsilon\}$.

   • From $A \rightarrow S$, $\text{FIRST}(A) = \text{FIRST}(S) = \{a, b, \varepsilon\}$.

   • From $B \rightarrow S$, $\text{FIRST}(B) = \text{FIRST}(S) = \{a, b, \varepsilon\}$.

2. FOLLOW Sets:

   • Start symbol is $S$, so \\in $\text{FOLLOW}$(S)$.

   • In $S \rightarrow aAbB$, after $A$ is $bB$, so $\text{FOLLOW}(A)$ contains $\text{FIRST}(bB) = \{b\}$.

   • In $S \rightarrow bAaB$, after $A$ is $aB$, so $\text{FOLLOW}(A)$ contains $\text{FIRST}(aB) = \{a\}$.

   • Thus, $\text{FOLLOW}(A) = \{a, b\}$.

   • In $S \rightarrow aAbB$ and $S \rightarrow bAaB$, $B$ is the last symbol, so $\text{FOLLOW}(B)$ contains $\text{FOLLOW}(S)$.

   • Since $A \rightarrow S$ and $B \rightarrow S$, $\text{FOLLOW}(S)$ contains both $\text{FOLLOW}(A)$ and $\text{FOLLOW}(B)$.

   • Thus, \text{FOLLOW}(S) = \{\\} \cup $\text{FOLLOW}$(A) \cup $\text{FOLLOW}$(B) = \{a, b, \$\}$, which gives$$\text{FOLLOW}$(B) = \{a, b, \$\}.

Therefore, $\text{FIRST}(A) = \{a, b, \varepsilon\} = \text{FIRST}(B)$, $\text{FOLLOW}(A) = \{a, b\}$, and \text{FOLLOW}(B) = \{a, b, \\}$, matching (A).