GWD-TN-14 20题 一个简单的问题，求解

Construction of the Roman Colosseum, which was
officially known as the Flavian Amphitheater, began in A.D. 69, during the
reign of Vespasian, was completed a decade later, during the reign of
Titus, who opened the Colosseum with a one-hundred-day cycle of religious
pageants, gladiatorial games, and spectacles.

A.     
which was officially known as the Flavian Amphitheater,
began in A.D. 69, during the reign of Vespasian,

B.      
officially known as the Flavian Amphitheater, begun in A.D.
69, during the reign of Vespasian, and

C.     
which was officially known as the Flavian Amphitheater,
began in A.D. 69, during the reign of Vespasian, and

D.     
officially known as the Flavian Amphitheater and begun in
A.D. 69, during the reign of Vespasian it

E.      
officially known as the Flavian Amphitheater, which was
begun in A.D. 69, during the reign of Vespasian, and

疑惑的地方是，如果原句是定语从句，是不是最好不要改？改成officially known as是做了插入语吗？这样句子的中心是否就转移了呢？

谢谢～～