Final answer:
The phase of the Report designer that lets you choose a color scheme is B) Styling Options, which is used to visually enhance the report's appearance.
Step-by-step explanation:
The phase of the Report designer that lets you choose a color scheme for report visualization is B) Styling Options. During the styling phase, designers can select color schemes that align with the brand or convey the right mood or emphasis for the data being presented. The option to change color schemes is not typically found in Visualization Setup, Data Configuration, or Presentation Settings, as these phases focus on other aspects of report design such as setting up data sources, designing the actual visualizations, and defining how the report will be presented, respectively.