D. It visually organizes the notes you take while reading.
A 3-column organizer is a note-taking strategy that involves dividing a piece of paper into three columns and labeling them with specific headings such as "main ideas," "supporting details," and "questions." This method helps students or readers to visually organize the notes they take while reading, making it easier to retain and recall information. By keeping notes organized and structured, readers can better understand the relationships between different pieces of information and remember key points from the text.
Therefore, option D is the correct answer.