This chart is showing they completed (let's say) 10 tasks in (let's say) 16 days when they projected it would take 21 days to complete 10 tasks.

A velocity chart is a tool used in agile project management to track the progress and performance of a project team over time. It shows the number of features or user stories completed in each iteration or sprint. The planned timeline line represents the expected or ideal velocity, while the actual effort line shows the actual or achieved velocity. By comparing the two lines, the Scrum master can identify any gaps, trends, or issues in the project delivery. Based on the image, the most likely update that the Scrum master can provide to the senior management team isD. The project is trending ahead of schedule. This is because the actual effort line is above the planned timeline line for most of the time, indicating that the project team is completing more features than expected in each sprint. This means that the project is ahead of schedule and has a positive velocity variance