The answer is B. I had the same question couple weeks ago
The answer to this question is Located <span>important routes for trade and travel
The lewis and clark expedition was also known as The corps of Discovery. This expedition was ordered shortly after united states bought Louisiana in order to explore the region. As it turned out, the expedition lead to several paths that could be used to travel natural resources, and the expedition contributed to the discoveries of most of United States western region today.</span>
Oh come on, don't make others write an entire essay for you.
I'll give you some ideas though!
Think of a world where supercomputers have blackmailed humanity by threatening nuclear war if there's no obedience
Think of a world where robots are so developed, the police/FBI/CIA use them to spy on each and every person
Think of a world where technology is so developed, we've trashed the environment and everything is dystopian and disgusting.
Best of luck!
The answer that best applies to both the Tang and Song dynasties would be C. A Reliable food production and distribution system. This gave both dynasties the ability to thrive.