Which among the following is not one of the five pillars of Islam?

The correct option is C The society should be divided with class hierarchy.
The five pillars of Islam are:

1)There is only one God, that is Allah and Mohammad is his Prophet.

2)All Muslims must offer prayers, called namaz five times a day.

3)Believers must fast from sunrise to sunset throughout the holy month of ‘Ramzan’.

4)They must give Zakat, or alms, to the poor.

5)They must make a pilgrimage to Mecca at least once in their lifetime.

Islam religion preached brotherliness and unity. It never insisted to form social hierarchies.