I believe the thesis in this is actually the first sentence considering the rest of the story talks about that first sentence.
Uhhh I dont know, I kinda suck at essays yk be honest
The correct option is A.
A map legend refers to the table or chart of visual explanation of the symbols that are used on a particular map. It serves as the key to understanding and reading the map correctly. Different colors are usually used to represent different features in order to show distinction among them. A map legend usually show symbols and the meaning of the of those symbols.
And neigh like Boanerges. That's the sound a horse makes so it makes sense.