Which of the following is an example of a conditional format rule?

Conditional formatting rules are designed to change the appearance of a cell or range of cells based on specific conditions or criteria. The option that states "Applying a green background to orders for a specific part" fits this definition perfectly, as it suggests that the background color is applied conditionally, depending on whether the cell matches a certain criterion relating to the specific part.

This approach allows users to visually analyze data more effectively by drawing attention to certain values or trends based on defined rules. In this case, the rule would only trigger (resulting in a green background) for orders that correspond to the specific part, distinguishing them from others.

The other options lack this conditional element; they describe formatting that is applied uniformly or universally across cells without regard to the value or conditions of the data within those cells.