Final answer:
The purpose of a separator bar in a menu is to separate and group together commands according to their purpose, which helps improve the organization and usability of the menu interface.
Step-by-step explanation:
The purpose of a separator bar in a menu is to separate and group together commands according to their function or relatedness. In a Menu Editor, a separator bar is created simply by typing a single hyphen (-) as the Caption, and even though it must have a unique name, it cannot be referred to in code, nor does it have a Click event. Therefore, the correct answer to the question is: 1) To separate and group together commands in the menu.