Correct Answer:
B. (B) Gutter
The correct answer is (B) Gutter. In typography and page layout, a gutter refers to the vertical separation or space between columns of text or between facing pages in a bound publication. It's crucial for readability and aesthetics, ensuring text from one column doesn't visually merge with another.
- (A) Index is an alphabetical list of names, subjects, etc., with references to the places where they occur.
- (C) Margin refers to the blank space between the edge of the page and the main body of the text. While related to spacing, it's distinct from the internal separation between columns.
- (D) None of these is incorrect because 'Gutter' precisely defines the vertical separation.