Final answer:
Al should click on Synchronous Scrolling after enabling View Side by Side to simultaneously scroll through two worksheets in different workbooks for comparison.
Step-by-step explanation:
If Al wants to compare data in two worksheets of two different workbooks quickly by scrolling through both at the same time, he should click Synchronous Scrolling after turning on View Side by Side on the View Tab in the Windows group. This feature will help Al to scroll through both worksheets simultaneously, allowing for a more efficient comparison. The other options such as Arrange All, Split, and Freeze Panes serve different purposes. Arrange All is used to arrange multiple opened workbook windows into a tiled layout, Split is for dividing the current worksheet into separate panes, and Freeze Panes is to lock a portion of the sheet to keep it visible while scrolling through the rest of the sheet.