Which describes a correct way to construct a scatterplot?

When analyzing the number of junk e-mails received each day of the week, the number of junk e-mails is the independent variable.

When analyzing the number of cups of hot tea that are sold during days with varying average temperatures, temperature is the dependent variable.

When analyzing shoe size according to height, shoe size is the independent variable
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When analyzing the number of boys who participate in volleyball each year for several years, the number of boys is the dependent variable.