Final answer:
The Symbol column is the optimal choice for visually representing the status of a row item through colors, as it can incorporate colored indicators and automate status changes.
Step-by-step explanation:
The best column type for visually representing the status of a row item with color, which can be automatically changed using a formula, would be a Symbol column. Symbol columns allow for the use of icons or other graphical symbols, which can include colored indicators. These symbols can quickly convey the status without the need for text and can be easily automated within spreadsheet applications to change based on formula outputs. While a Dropdown List column can also represent status, it is limited to text and does not provide the immediate visual cue that color does.