Which of the following allows customization of worksheet appearance?

Adjusting worksheet formatting enables users to customize the visual aspects of a worksheet, enhancing its appearance and readability. This includes modifying elements such as font type, size, and color; cell background colors; borders; and alignment settings. By applying these formatting options, users can create a more visually appealing and organized layout, which can help convey information more effectively to viewers.

While creating a new workbook generally sets the stage for future work, it does not directly contribute to customization of an existing worksheet's appearance. Modifying filter expressions is primarily focused on data manipulation and visibility rather than visual styling. Implementing data validation is crucial for maintaining data integrity and ensuring that the entered data meets specific criteria but does not affect how the worksheet appears visually. Thus, the option that directly addresses appearance customization is through adjusting the worksheet formatting.