Final answer:
A Pareto chart is best because it allows you to see which sources account for most of the electricity and the bars make it easy to visually compare the different percentages.
Step-by-step explanation:
A Pareto chart is best because it allows you to see which sources account for most of the electricity. A pie chart should not always be used when comparing percentages. The bars in a Pareto chart make it easy to visually compare the different percentages.