Final answer:
Edward should create a line chart to show the trend in iPod sales over the past 2 years.
Step-by-step explanation:
To show the trend in iPod sales over the past 2 years, Edward should create a line chart. A line chart is an effective way to display changes and trends over time. Each point on the chart would represent the number of iPod sales during a specific time period, such as each month or quarter of the past 2 years. Connecting these points with a line would allow Edward to visualize the overall trend in iPod sales.