D) “Both emperors unifi[ed China after years of war and rebellion]” is correct.
Some background information:
Shi Huangdi, also known as Qin Shi Huang, was the emperor who unified China and made it a centralised empire.
Li Yuan, also known as Gaozu of Tang, was the founder of the Tang dynasty in China.
On with the question! :)
Firstly, we need to cancel A), because Li Yuan was never known to have burned any books. Shi Huangdi, on the other hand, arguably did because he wanted to encourage the philosophy he believed in, Legalism, over everything else.
Secondly, we need to cancel B).
The Silk Road was really cultivated (not built, because it wasn't an actual road) during three periods: the Han dynasty, the Tang dynasty, and the Pax Mongolica—but not the Qin dynasty. Yes, Li Yuan helped facilitate the Silk Road, but Shi Huangdi didn't.
Thirdly, we need to cancel C). Yes, Shi Huangdi’s tomb is large, notably being divided into inner and outer cities. However, Li Yuan’s tomb does not occupy such a vast territory; therefore this is incorrect.
Finally, D) “Both emperors unifi[ed China after years of war and rebellion]” is correct.
(The full part wasn’t displayed in the question, so I went ahead and found the full question on Google.)
Shi Huangdi was the first emperor to turn China into a centralised empire, forming the Qin dynasty.
The fall of the Sui dynasty, the dynasty before the Tang, caused China to be decentralised for years. It was finally united again under the Tang—under Li Yuan, after years of civil war in the aftermath of the fall of the Sui dynasty.