The correct answer is D.
The dictates of Islam consider the three principles listed. On the first hand, that all believers are equal. The existing divisions in the Muslim communities have been actually created by men due to many reasons which are not connected to the teachings of the religion, such as: race, sect, our pre-Islamic cultures, political opinions, ancestry.
All Muslims pray facing Mecca and the pilgrimage to this city once in lifetime is actually one of the mandatory religious duties for all of them. Every Muslim has to read the Quran as well, and needs to learn Arabic in order to do so.