What is a vertical cross section, and please include a picture or explain if you can. (Don't copy and paste of googl, write in your own words i just need it for my notes.)

Amanda went into the grocery business starting with five stores. after one year, she opened two more stores. after two years, she opened two more stores than the previous year. if amanda expands her grocery business following the same pattern, which of the following graphs represents the number of stores she will own over time?