For each of the following situations, choose one of these as an appropriate display: single pie chart, bar graph, histogram, side-by-side boxplots, or scatterplot.
a. 1st-grade boys' heights and weights
b. Heights of 1st-grade girls
c. Whether a 1st-grade student is a boy or a girl, and whether he/she is light, medium, or heavy
d. Heights of 1st-grade girls compared to heights of first grade boys