Final answer:
Cell styles in Excel are used to quickly apply different formatting to a workbook. They include predefined sets of formats for fonts, colors, borders, and number formats.
Step-by-step explanation:
The formatting technique that can be used to quickly apply different formatting to an Excel workbook is D) Cell styles. Cell styles in Excel are a set of predefined formats that you can apply to cells with a single click. These styles can include fonts, colors, borders, and number formats.
Conditional formatting is also a feature in Excel which allows you to apply formatting to cells depending on the cell's value. For example, you could highlight all cells in a range that are greater than a certain number. While it is useful for visualizing data patterns, it is not specifically for applying a set style across the workbook like cell styles are.
Data validation is used to control the type of data or the values that users enter into a cell. And a PivotTable is a powerful tool to summarize, analyze, explore, and present data, not a formatting technique.