To identify the sentence that is best supported by the map identify the idea the map conveys and select the sentence that explains this idea.
A supporting sentence or element such as an image, map, graph, etc. helps the author explain an idea. For example, the idea "Leonardo Da Vinci's paintings are impressive" can be supported by adding an image of the Mona Lisa.
These are the steps you can follow:
Note: This question is incomplete because the map and text are missing; due to this, I answered it based on general knowledge.
Learn more about maps in: https://brainly.com/question/9241109