C. Islam. Explanation: Muhammad (founder of Islam) was born and Mecca. He later fled to Medina with Abu Bakr later in his life (due to the hate that he was getting for his religion in Mecca. ) also the kaaba (a shrine for muslims) is locates in Mecca. ALSO, Mecca is Islam’s holy city which only Muslims are allowed to enter. ALSO, Muslims have to follow the five pillars of Islam which includes hajj ( or pilgrimage) meaning that at least once in their life a Muslim will have to travel to Mecca