Step-by-step Solution:

Solution Breakdown

The problem uses a substitution cipher where each letter in the original word is replaced by its "opposite" letter in the English alphabet.

An opposite letter pair is formed by pairing the first letter of the alphabet with the last, the second with the second-to-last, and so on (A=Z, B=Y, C=X, etc.).

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Step 1: Analyze the Example (BEAT → YVZG)

We can verify the pattern using the given example:

• The opposite letter for B is Y.
• The opposite letter for E is V.
• The opposite letter for A is Z.
• The opposite letter for T is G.

The rule is confirmed to be the opposite letter substitution.

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Step 2: Apply the Pattern to MILD

Now we apply the same rule to each letter of the word MILD:

• The opposite letter for M is N.
• The opposite letter for I is R.
• The opposite letter for L is O.
• The opposite letter for D is W.

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Conclusion

Combining these letters gives us the coded word NROW.

This corresponds to option D.