Which key is used to copy the formula from the above cell:

The correct answer is Ctrl+Apostrophe ('). This keyboard shortcut in spreadsheet applications like Microsoft Excel is specifically used to copy the formula from the cell directly above the active cell into the active cell, displaying the formula itself rather than its calculated result. This is particularly useful for quickly replicating or inspecting formulas.

• Ctrl+C is used to copy the selected content (value or formula) to the clipboard, not specifically from the cell above.
• Ctrl+: (Ctrl+colon) is used to insert the current time.
• Ctrl+. (Ctrl+period) is used to select the corners of the selected range.