Step 1: Understanding the Concept:
In geometry, art, and design, a line is a fundamental element. Lines can be classified based on their orientation.
Step 2: Detailed Explanation:
- Horizontal lines are straight lines that run from left to right, parallel to the horizon.
- Vertical lines are straight lines that run up and down, perpendicular to the horizon.
- Diagonal lines are straight lines that are slanted, connecting two non-adjacent corners.
All three are basic and distinct types of lines used to create shapes, forms, and direction in visual arts and technical drawings.
Step 3: Final Answer:
Horizontal, vertical, and diagonal are all fundamental types of lines. Therefore, the correct answer is 'All of these'.