The correct answer is B. Great Wall
Step-by-step explanation:
Qin Shi Hung or Quin emperor of China lived during the 2nd century B.C. and it is considered as the first emperor of China as he unified all the states of China to ruled them. During his rule, Qin Shi aimed at expanding China and creating reforms to standardize the practices in the different Chinese states. Also, Quin Shi Hung is recognized for building the Great Wall of China by unifying some of the existing walls previously built during the 7th century B.C. in each state, in this way all the states were protected from invasions and attacks of nomadic groups which make the defense of the unified country stronger. Thus, the fortification Qin emperor built to make china's defense stronger was the Great Wall.