Step 1: Understanding the Quote.
The quote "An unexamined life is not worth living" is attributed to Socrates, one of the most influential philosophers of ancient Greece. Socrates believed that the key to living a meaningful life was constant self-examination and questioning of one’s beliefs and actions.
Step 2: Analyzing the Options.
- 1. Plato: Although Plato recorded Socrates’ dialogues and teachings, the quote itself is attributed to Socrates.
- 2. Buddha: Buddha focused on enlightenment and the cessation of suffering but did not express this idea.
- 3. Socrates: This is correct. Socrates famously said that the unexamined life, devoid of reflection and inquiry, is not worth living.
- 4. Tagore: Rabindranath Tagore was a poet and philosopher, but this quote is not attributed to him.
Step 3: Conclusion.
The correct answer is 3. Socrates.
Final Answer:
\[
\boxed{\text{The correct answer is 3. Socrates.}}
\]