Concept:A trellis drainage pattern forms where alternating bands of hard and soft rock create parallel ridges and valleys.Explanation:In such areas, the main river cuts across the ridges.Hard rocks resist erosion and stand out as ridges, while soft rocks erode faster to form valleys.Tributaries of the main river develop in these softer valleys.They join the main river at nearly right angles, resembling a garden trellis.This pattern is best developed where alternate hard and soft rocks lie parallel to each other.Answer:C. Trellis