Distil Complex Data Into One Chart

You have a messy spreadsheet and one slide to make a non-specialist audience see the point. This recommends the single best chart for the insight you care about, explains why over what merely looks nice, and tells you exactly what goes on each axis and what to highlight. Less decoration, more decision.

I need to present the following data set to a non-specialist audience and I must represent it in a single chart. Here is the data:
{DATA_OR_DATA_DESCRIPTION}

The key insight I want the audience to take away is: {KEY_INSIGHT}

Please:
1. Recommend the single most effective chart type for this insight and explain why (not just what looks nice)
2. Describe exactly what goes on each axis, what should be highlighted or annotated, and what should be removed or simplified
3. Write a chart title that states the conclusion, not just the subject
4. Write a one-sentence caption that reinforces the insight for slower readers
5. Warn me of any ways this chart could be misread and how to prevent that

Do not suggest multiple chart options. Commit to the best one.