Final answer:
Out of the five sons of Pir Sadardin, Hasan and Hussain became Pirs. This reflects their role as spiritual leaders in the Muslim community, specifically within the Ismaili sect.
Step-by-step explanation:
The sons of Pir Sadardin who became Pirs are Hasan and Hussain, according to historical records. Therefore, the correct answer to the question is a) Hasan and Hussain. In the context of Islamic history, the term Pirs often refers to spiritual leaders or guides, particularly in certain Sufi traditions. Pir Sadardin is a historical figure of significance in certain Muslim communities and notably within the Ismaili branch of Shia Islam.