Changing the size of the picture:
3a) A bar graph, or line graph will show the information accurately.
3b) Yes I would continue. The graph shows that over the weeks, there are more and more items that are being sold.
4) I would choose the line graph to show Mrs.Mota. The reason why I would choose the line graph is because the line graph is best to show data over time and the line graph shows the trend.