Question

In the West, __________ was called Othman, and his followers were known as Ottomans.

a. Suleyman I
b. Osman
c. Timur
d. Mehmed II

Answer 1

Othman is the same person and the same name as Osman - so the correct answer is b). Othman or Osman started the house of Osman in Turkey

In fact, in some European languages this is still seen, for example in German the Ottoman Empire is called "Osmanisches Reicht" - the Empire of Osman.