Step 1: Understanding the Concept:
Translate the physical circuit diagram into logical symbols.
Step 2: Key Formula or Approach:
Series $\rightarrow \wedge$. Parallel $\rightarrow \vee$.
Step 3: Detailed Explanation:
The main path goes through $S_1$. Then it branches into $S_2$ and $S_3$.
This is $p \wedge (q \vee r)$.
The extra wire at the bottom contains $S_1, S_2, S_3$ all in series, which is redundant.
Step 4: Final Answer:
The simplified form is $p \wedge (q \vee r)$.