Final answer:
A Shia religious school is least likely to teach the recognition of the first three caliphs as legitimate, as Shia Islam maintains that Ali was the first rightful imam. Other Shia beliefs such as the Five Pillars, infallibility of imams, and mourning of Imam Hussein are commonly taught.
Step-by-step explanation:
A student in a Shia religious school would be least likely to learn the tenet recognizing the first three caliphs (Abu Bakr, Umar, and Uthman) as legitimate leaders of the Muslim community. This is because Shia Islam holds that Ali, Muhammad's cousin and son-in-law, was the first rightful imam and successor to Muhammad, which differs from the Sunni Muslim belief. The question pertains to the period immediately following the death of Prophet Muhammad and the subsequent leadership dispute that led to the Sunni-Shia split. The other options mentioned, such as the importance of the Five Pillars of Islam, the belief in the infallibility of the imams, and the mourning ceremonies for Imam Hussein, are all integral aspects of Shia Islam and would be taught in a Shia religious school.
The Shia branch of Islam recognizes Ali and the imams descending from him as possessing both spiritual and political authority, and this lineage is believed to transmit divine knowledge and guidance. The mourning of Imam Hussein, a central figure in Shia Islam and the son of Ali, is a particularly important religious observance that commemorates his martyrdom at the Battle of Karbala.
In summary, the contention related to the caliphate and the recognition of the early caliphs is a fundamental doctrinal difference between Sunni and Shia Islam, affecting what is taught in religious schools adhering to each branch.