In this English grammar error spotting question, one part of the sentence may be incorrect. Identify the part with the error, or choose the "No error" option. Sentence: I left no stone unturned to achieve for my object.

Introduction / Context:
This error spotting question focuses on correct idiomatic usage in English. The sentence uses the common expression "leave no stone unturned", which means to make every possible effort. However, there is an error in the phrase that follows this idiom. You must spot the incorrect part and understand what the correct structure should be.

Given Data / Assumptions:
- Full sentence: I left no stone unturned to achieve for my object.
- Part A: I left
- Part B: no stone unturned
- Part C: to achieve for my object
- Part D: No error

Concept / Approach:
The idiom "leave no stone unturned" is correctly used in parts A and B. The error lies in the phrase "to achieve for my object". In English, we say "to achieve my object" or "to achieve my objective", without inserting "for" between "achieve" and its object. The preposition "for" is unnecessary and ungrammatical in this context, so part C is incorrect.

Step-by-Step Solution:
Step 1: Recognise that "I left no stone unturned" is a standard idiom and is correctly used. Step 2: Focus on the remaining part "to achieve for my object". Step 3: Recall standard usage such as "to achieve my goal", "to achieve my aim", or "to achieve the objective". Step 4: Realise that adding "for" after "achieve" breaks the normal verb object pattern. Step 5: Conclude that part C contains the error and should be corrected to "to achieve my object".

Verification / Alternative check:
You can verify by reading similar correct sentences: "He left no stone unturned to achieve his target", "She worked hard to achieve her dream". None of these include "for" after "achieve". Grammar references and dictionaries list "achieve something" as a direct transitive verb pattern, which supports the conclusion that the preposition "for" is unnecessary and wrong here.

Why Other Options Are Wrong:
Part A simply contains the subject and verb and is correct. Part B correctly uses the idiom "no stone unturned". Part D, "No error", is incorrect because an error has been identified in part C. Option E, stating that there is no error in any part, also cannot be correct for the same reason.

Common Pitfalls:
Students sometimes insert extra prepositions out of habit, especially after verbs like "discuss", "order", or "achieve", leading to incorrect phrases such as "discuss about", "order for", or "achieve for". To avoid this, remember the basic patterns of common verbs and review lists of transitive verbs that do not require a preposition before their object.

Final Answer:
The error is in part C, because the phrase should be "to achieve my object", not "to achieve for my object".