Step 1: Idea: find the odd pair out:
Three pairs are true and one is false. We name the home country of each thinker from memory and spot the one that does not fit.
Step 2: The sixth century BCE thinkers:
The sixth and fifth centuries BCE saw thinkers across the world: Zarathustra in Iran, Kong Zi in China, Mahavira and the Buddha in India, and Socrates, Plato and Aristotle in Greece.
Step 3: Compare with the list:
Iran, China and India are correctly matched in the first, second and fourth options. The third option names Germany, but the correct country is Greece.
Step 4: Remember the question asks for the wrong one:
Since the question asks for the incorrect match, the answer is the third option.
Final Answer:
Socrates is from Greece, so matching him with Germany is the only wrong pair, option 3.
\[ \boxed{3} \]