Final answer:
To change the fill color of the 2019 data point to Green, Accent 6 in a chart, the student should select the last color option in the first row under Theme Colors, which is option D) Last.
Step-by-step explanation:
The student is asked to change the fill color of a data point in a chart to Green, Accent 6, which is specified to be the last option in the first row under Theme Colors. To accomplish this, the corresponding color option to select would be D) Last. This color change will visually distinguish the 2019 data point in the Gross Profit series on a chart, likely made in spreadsheet software such as Microsoft Excel.