Terra Cota warriors

[swapna]

Rivaling the pyramids of Egypt or even the ancient cities of the Maya as an achievement, the army of terra-cotta warriors created to protect Qin Shi Huang, China’s first emperor, in his afterlife is more than 2,000 years old and took 700,000 artisans more than 36 years to complete them.

A. took 700,000 artisans more than 36 years to complete them
B. took 700,000 artisans more than 36 years to complete it
C. took 700,000 artisans more than 36 years to complete
D. 700,000 artisans took more than 36 years to complete
E. to complete them too 700,000 artisans more than 36 years

OA is B. I was confused between option B and C. Could you please explain why would we require it at the end of the sentence. Wouldn't "it" here create an ambigous pronoun?

[muralidharin]

OA is wrong. Correct answer is C

[jnelson0612]

The correct answer is indeed C. Here is a link about this problem: gmatprep-t6880.html