Step 1: Understanding the Question:
This question tests knowledge of planting techniques in salt-affected soils.
Step 2: Detailed Explanation:
In raised bed planting systems, seedlings should be planted at the top of the bed in salt-affected soils.
Salt accumulates in the furrow and mid-slope due to evaporation and upward movement of water.
The top of the bed has lower salt concentration.
Thus, planting at the top reduces salt stress.
Step 3: Final Answer:
Thus, seedlings should be planted at the top of the bed, which corresponds to option (A).
[0.5cm]