In the following English sentence, identify the part that contains an error, or choose No error if the sentence is correct: Had I been in the position of my brother, I would have refused the offer.

Introduction / Context:
Error spotting questions in English grammar test your understanding of tense, conditional structures, and sentence patterns used in formal writing. The sentence here uses a conditional construction beginning with Had I been, which is a slightly formal, inverted form of a third conditional clause.

Given Data / Assumptions:
- Sentence: Had I been in the position of my brother, I would have refused the offer. - Part A: Had I been. - Part B: in my brother s position. - Part C: I would have refused the offer. - Part D: No error.

Concept / Approach:
This sentence expresses an unreal past condition and its possible past result. English uses the third conditional for such situations. The standard form is If I had been in my brother s position, I would have refused the offer. In formal usage, the if clause can be inverted by dropping if and placing had at the beginning: Had I been in my brother s position. Both forms are grammatically correct. The main idea is that the speaker was not actually in that position but imagines what would have happened if he were.

Step-by-Step Solution:
Step 1: Check Part A, Had I been. This matches the correct inverted third conditional form. Step 2: Check Part B, in my brother s position. This correctly describes a hypothetical role and follows the verb been. Step 3: Check Part C, I would have refused the offer. This is the correct form of the result clause in a third conditional, would have plus past participle. Step 4: Since all three parts follow correct grammar rules, there is no error in any segment. Step 5: Therefore, the correct choice is the option that states No error.

Verification / Alternative check:
Rewrite the sentence using if to verify: If I had been in my brother s position, I would have refused the offer. This structure is clearly correct for unreal situations in the past. When we invert the clause to Had I been in my brother s position, the meaning and tense remain exactly the same, so the grammar must still be correct.

Why Other Options Are Wrong:
Option A is correct because Had I been is a valid inversion of If I had been. Option B is correct because in my brother s position properly follows the verb been and uses a natural expression. Option C is correct because would have refused is the right verb form in the result part of a third conditional sentence.

Common Pitfalls:
Learners sometimes think that any sentence starting with Had must be wrong because they are more familiar with if clauses. Another common mistake is to try to change would have refused to would refuse or will refuse, which would break the time reference and conditional type. Remember that third conditional sentences describing unreal past situations use had plus past participle in the condition clause and would have plus past participle in the result clause.

Final Answer:
The sentence is correct, so the right choice is D, No error.