The correct answer is D. Pilgrimage.
Explanation
Islam is a monotheistic religion, its holy book is the Koran, which states that the only God is Allah and his prophet was Mohammed. The individuals who follow this religion are called Muslims. According to the scriptures, Muhammad was the last prophet sent by God. It is also believed that Coran was transmitted by God to Muhammad through Gabriel Archangel. One of its principles is Hajj, a term that refers to the pilgrimage that Muslims must make to Mecca in Saudi Arabia at least once in their life. So, the correct answer is Pilgrimage.
