Ever since it was built three centuries ago, the Taj Mahal in Agra, India, was described as the most beautiful building in the world.
a) was described as the most beautiful building
b) had been described like the prettiest building
c) has the description of being a building richest in beauty
d) has been described as the most beautiful building
e) has been described as the beautifulest building
Source: GMAT Club Ultimate Grammar
Straight for d:
A and C are gone because "Since" requires perfect tense.
B is gone because Past Perfect is used without context, thus wrong.
E is gone because of the "beautifulest".
D is right.
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