Step 1: Understanding the Question:
This question tests knowledge of urban forestry and planting methods.
Step 2: Detailed Explanation:
Tall seedling planting is the most common method for establishing urban avenues.
Tall seedlings (2-3 m height) are used for immediate impact.
Tall tree planting (A): Not common.
Normal seedling planting (C): Used in plantations.
Stump planting (D): Used in forestry.
Thus, the correct answer is tall seedling planting.
Step 3: Final Answer:
Thus, tall seedling planting is the most common method, which corresponds to option (B).
[0.5cm]