Which of the following CSS properties is used to add space between inline elements?

The correct choice involves the use of the margin property to create space between inline elements. When dealing with inline elements, such as <span> or <a>, the margin property allows you to control the external space surrounding these elements. By applying margin to the left or right of an inline element, you can effectively create the desired separation, enhancing the overall layout and readability of your content.

In contrast, while padding can also affect spacing, it specifically adds space within the element itself, between the element's border and its content, rather than between different elements. Line-height is primarily used for controlling the vertical spacing between lines of text within a block of content, not between inline elements. The term "spacing" isn't a standard CSS property; therefore, it wouldn't be applicable in this context. Using margin is the most appropriate way to manage space in this scenario.