Which of these countries has a majority Shiite Muslim population?

Iran is recognized for having a majority Shiite Muslim population, which distinguishes it as the center of Shiite Islam. The Islamic Republic of Iran has established itself as a Shiite theocracy, where Shiite beliefs, practices, and governance play a vital role in national identity and policy. Approximately 90-95% of Iran's population identifies as Shiite, making it the largest Shiite-majority nation in the world.

In contrast, Saudi Arabia has a significant Sunni Muslim majority, predominantly adhering to the interpretation of Islam known as Wahhabism. Morocco has a mixed Muslim population predominantly identifying as Sunni, while Indonesia, the world’s largest Muslim-majority country, also primarily follows Sunni Islam. Therefore, Iran's significant Shiite demographic sets it apart and confirms it as the correct answer to the question about majority Shiite Muslim populations.