Step 1: Understanding the Question:
This question tests knowledge of agroforestry research methods.
Step 2: Detailed Explanation:
Macro Design and Diagnostic (MDD) survey in agroforestry is aimed at the regional level.
It is used to assess the potential of agroforestry systems in a region.
Country level (A): Not MDD.
State level (C): Not MDD.
Local level (D): Not MDD.
Thus, the correct answer is regional level.
Step 3: Final Answer:
Thus, MDD survey is aimed at the regional level, which corresponds to option (B).
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