When checking the "Straight Enough" condition,which is the best graph to look at?

A) Residual plot.
B) Histogram
C) Boxplot
D) Scatterplot
E) Pie Chart

The "Straight Enough" condition refers to checking whether the relationship between two variables is linear or not. The best graph to look at for this purpose is a scatterplot, as it allows us to visually inspect the relationship between the variables. If the scatterplot shows a roughly linear relationship between the variables, then we can say that the "Straight Enough" condition is met. Other graphs like residual plots, histograms, and boxplots are useful for checking other assumptions of regression, but not specifically for the "Straight Enough" condition. A pie chart is not relevant for visualizing the relationship between two variables.