Final answer:
The desired gridline style is B) Dash, which consists of short dashes with spaces in between. This style is different from Solid, Dotted, or Double styles.
Step-by-step explanation:
The desired style for the gridlines when instructed to change them to use the Dash (dash style) is the Dash style. This is an option available in many programs that allow customization of gridline appearance, such as spreadsheet applications or graphing software. When changing the gridline style to Dash, the lines will appear as a series of short dashes with spaces in between, rather than as solid, continuous lines. It's important to differentiate between the available styles, such as Solid, Dash, Dotted, and Double, as each provides a unique visual cue on the grid. The answer to the question is B) Dash.