The question asks which compound shows retention of configuration when undergoing nucleophilic substitution by $\ce{OH^-}$.

However, the actual structures/options A, B, C, D are missing from the prompt. Since retention/inversion/racemization depends completely on the substrate structure and mechanism, the answer cannot be derived rigorously without seeing the compounds.

1. Key idea

For nucleophilic substitution:

1. $\mathrm{S_N2}$ reaction gives inversion of configuration (Walden inversion).
2. $\mathrm{S_N1}$ reaction usually gives racemization (often partial racemization).
3. Neighbouring group participation / double inversion can lead to overall retention of configuration.

So, the correct compound must be one whose structure allows retention, usually through:

• neighbouring group participation,
• cyclic intermediate formation,
• or a sequence equivalent to double inversion.

2. Limitation in this problem

The options are shown as:

• A:
• B:
• C:
• D:

but the chemical structures are not provided. Therefore, a step-by-step structural comparison is not possible from the given data alone.

3. Comparison with stored answer

The stored correct answer is C. Since the actual options are missing, I cannot independently verify it from first principles here. But if the exam source marks C, then likely option C is the substrate that undergoes substitution with overall retention of configuration, probably via neighbouring group participation / double inversion.

Thus, based only on the provided stored answer, I will report C, while noting that the question statement is incomplete without structures.