Which tool allows you to create straight lines in Illustrator?

The Line Segment tool is specifically designed for creating straight lines in Adobe Illustrator. When selected, this tool lets you click and drag to create a line at any angle, enabling precise control over the length and direction of the line. This direct functionality is ideal for users looking to create simple graphics or outlines quickly.

In contrast, the Pencil tool is used primarily for freehand drawing and does not guarantee straight lines, as it mimics the way a physical pencil would behave on paper. The Brush tool is designed for creating strokes that follow the shape of custom brushes, which can also result in curved or varied lines rather than straight ones. The Pen tool, while capable of creating straight lines through points, requires more complex usage with anchor points and path segments, making it less immediately effective for users simply needing to draw straight lines. So, the Line Segment tool stands out as the most straightforward and efficient choice for creating straight lines.