Which of the following regions saw the emergence of Zarathustra as an influential thinker?

Iran

The mid-first millennium BCE marks a pivotal juncture in human history, characterized by the rise of influential thinkers across different regions, each seeking to unravel the enigmas of existence and comprehend the connection between humanity and the cosmic order. During this era, numerous profound minds emerged in various parts of the world. In Iran, Zarathustra made significant contributions, while Kong Zi left a lasting impact on China. Meanwhile, Greece witnessed the remarkable philosophies of Socrates, Plato, and Aristotle, and in India, Mahavira and Gautama Buddha emerged as prominent figures.