The passage is mainly discussing ______.

A．Unlike Francisco Goya, Pablo Picasso and several Mexican artists expressed their political opinions in their painting.
B．History books often reveal the compilers' political views.
C．Religious art remained in Europe for centuries the only type of art because most people regarded the Bible as the Holy Book.
D．In the Middle East even today you can hardly find any human and animal figures on palaces or other buildings.

A．Islamic artists have had to create architectural decoration with images of flowers or general forms
B．history teachers are more objective than artist
C．it is more difficult to study art history than general history
D．people and stories from the Bible were painted on churches and other buildings in order to popularize the Bible