Why is drainage critical in earthwork and how is it integrated into design?

• A. Proper drainage prevents subgrade instability and erosion; integrated via ditches, swales, culverts, and grade lines.
• B. Drainage only affects finished surface appearance; integrated via cosmetic landscaping.
• C. Drainage is not important if soil is stable; no integration needed.
• D. Drainage is achieved by paving thicker asphalt; no water management features needed.

Answer: (A)