India is called a secular country because citizens have the fundamental right to:

freedom to profess religion of one's choice

The correct answer is Option 4 - freedom to profess the religion of one's choice

India is considered a secular country because its Constitution ensures that citizens have the fundamental right to freedom of religion. This right is enshrined in Article 25 to Article 28 of the Indian Constitution. It guarantees individuals the freedom to profess, practice, and propagate religion of their choice without interference from the state. This secular principle promotes equality and respects the diversity of religious beliefs and practices within the country.