Answer : 3. "राज्य का प्रमुख एक निश्चित अवधि के लिए चुना जाता है "
Explanation :

India is a republic because the head of the state, the President, is elected by an electoral college for a fixed term of five years. This democratic process ensures that the highest office in the country is not hereditary but held through periodic elections, reflecting the nation's commitment to representative governance and equality.