The answer for the 1st blank is text.
<span>C. 3
Due to the different speeds of P and S waves, a single seismometers can determine the distance to an earthquake. So, for a single station, the localization is any point on a circle around the station. With 2 stations, you'll have two circles that intersect at two points. The 3rd station is needed in order to determine which of the 2 points is the actual earthquake.</span>
Static void DashedLine(int n){ if (n>1) Console.WriteLine(new String('-', n));}
