It's A. Because a simile is a fugue of speech involving the comparison of one thing to another thing of a different kind.
With the A. migration of people from fertile areas, knowledge of agriculture spread by diffusion.
When people migrate from a place, they move into other areas. When something diffuses, it spreads around.
The firefighters would pass buckets to each other to extinguish the blaze. ... On October 9, 1871 the infamous "Chicago Fire" killed 300 people, but there was an even more tragic fire that same day that killed 1200 ... What is the Star of Life?