Step 1: Understanding the Question:
This question tests knowledge of wood preservation methods.
Step 2: Detailed Explanation:
The pressure process is the most common method of wood preservation in India.
It involves forcing preservatives into wood under pressure.
Boucherie process (A): For green wood.
Superficial process (B): Only surface treatment.
Soaking and diffusion (C): Not as common.
Thus, the correct answer is the pressure process.
Step 3: Final Answer:
Thus, the most common wood preservation method is the pressure process, which corresponds to option (D).
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