Final answer:
A bar graph is the most suitable option to compare the sales of different coffee flavors because it effectively shows the differences in sold quantities among discrete categories. It is better than histograms, line graphs, or scatter plots for this type of categorical comparison.
Step-by-step explanation:
The question asks which graph would be the best to compare how much of each coffee flavor is sold on a Saturday morning. A bar graph is the best choice for this comparison because it is ideal for showing and comparing discrete categories, in this case, the different flavors of coffee. Each bar would represent the amount of coffee sold for each flavor, allowing for easy comparison. Unlike histograms, which are better for continuous data, or line and scatter plots, which are used for showing trends or relationships over time or between variables, a bar graph clearly shows the differences in quantities among categories in a visual and straightforward manner.
Regarding slope, in the context of line graphs, a positive slope indicates that as one variable increases, the other also increases. A negative slope indicates that as one variable increases, the other decreases. A zero slope, however, signifies that there is no change in the variable's value despite changes in the other variable, appearing as a horizontal line.