S = – 25m2 + 125m, where S is the number of CDs sold in thousands, and m is the number of months that it is on the market.
a. In what month should the music store expect the CD to stop selling?
b. In what month will CD sales peak?
c. How many copies will the CD sell at its peak?

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?