The correct answer is: B. margin
A margin is the blank space around the edge of a page. It is used to separate the text from the edge of the page and to provide space for notes and comments.
A border is a decorative or functional design that is placed around the edge of a page. It can be made of lines, shapes, or images.
A blank is a space that is left empty. It can be used to separate different parts of a text or to provide space for additional information.
A gap is a space between two things. It can be used to separate different parts of a text or to provide space for additional information.
In the context of the question, the correct answer is “margin” because it is the space that is left around the edge of a page. This space is used to separate the text from the edge of the page and to provide space for notes and comments from the teacher.