What is the space between the binding side and the paragraph called?

The correct answer is Gutter Margin.

• A Gutter Margin is an additional space added to the side margin, top margin, or inside margin of a document that you plan to bind. This extra space ensures that text is not obscured when the document is bound, allowing for comfortable reading.
• Line Spacing (A) is the vertical distance between lines of text.
• Indentation (B) is the space from the margin to the start of a paragraph.
• Justification (D) refers to the alignment of text along the margins.

The gutter margin is crucial for documents like books or reports to prevent text from disappearing into the binding.