Final answer:
To select several contiguous columns, you click the header of the first column, press and hold Ctrl, and click the header of the last column.
Step-by-step explanation:
The correct option to select several contiguous columns is D) click the header of the first column, press and hold Ctrl, and click the header of the last column. By holding the Ctrl key while clicking the headers of the first and last columns, you can select multiple columns at once. This allows you to perform operations or formatting on the selected columns simultaneously.