Final answer:
To auto-fit a column in Excel, right-click on the column header and select 'Auto Fit Column Width'.
Step-by-step explanation:
The best way to auto-fit a column to the data in Microsoft Excel is by right-clicking on the column header and selecting 'Auto Fit Column Width'. This will automatically adjust the column width to fit the longest value in that column.
Option 2 is incorrect because double-clicking on the column header will only adjust the width to fit the header text, not the data.
Option 3 is also incorrect because there is no 'Format' tab in Microsoft Excel. The correct option is the first one, which is right-clicking on the column header and selecting 'Auto Fit Column Width'.