The sentence is split into labelled parts: "Writing also helped A to improve the B vocabulary, whether it was C vernacular or English". Choose the most logical order of the labels to form a coherent sentence.

Introduction / Context:
This question is a sentence reordering task where a sentence has been broken into labelled segments A, B and C. The base frame is "Writing also helped" and the segments are "to improve the", "vocabulary, whether it was" and "vernacular or English". Your task is to decide the order of these labels so that the final sentence is grammatically correct and logically meaningful. Such questions are common in English sections of competitive exams and help test your intuitive sense of sentence structure and collocation.

Given Data / Assumptions:

• The basic beginning is "Writing also helped".
• Segment A is "to improve the".
• Segment B is "vocabulary, whether it was".
• Segment C is "vernacular or English".
• The options are different permutations of A, B and C: CBA, ABC, CAB, BCA and ACB.
• We assume the intended sentence refers to vocabulary in both vernacular and English forms.

Concept / Approach:
The natural English phrase here is "Writing also helped to improve the vocabulary, whether it was vernacular or English." We notice the pattern "helped to improve" followed by the object "the vocabulary". After that comes an explanatory clause "whether it was vernacular or English" which adds detail about the type of vocabulary. Therefore, A must come directly after "helped", B should follow A to complete the noun phrase, and C will finish the clause. The logical order is thus A, B and C. The approach is to look for familiar collocations and the standard position of infinitive phrases and objects in an English sentence.

Step-by-Step Solution:
Step 1: Attach A to the opening: "Writing also helped to improve the". This reads naturally as a verb phrase. Step 2: Continue with B: "Writing also helped to improve the vocabulary, whether it was". Now we have a complete object "the vocabulary". Step 3: Finish with C: "Writing also helped to improve the vocabulary, whether it was vernacular or English". Step 4: Note that this sequence uses the labels in the order A, then B, then C, which corresponds to option ABC.

Verification / Alternative check:
Test the other possible sequences. If we try CBA, the sentence would read "Writing also helped vernacular or English vocabulary, whether it was to improve the", which is clearly wrong. CAB would place "vernacular or English" before "to improve the vocabulary", giving an awkward and ungrammatical sentence. BCA and ACB also break the close connection between "to improve" and "the vocabulary". Only ABC maintains the correct infinitive structure and the natural flow from verb to object to descriptive clause, confirming that it is the only acceptable order.

Why Other Options Are Wrong:
CBA begins with "vernacular or English" directly after "helped", which leaves the verb "helped" without its proper infinitive complement and misplaces the phrase that should finish the clause. CAB puts "vernacular or English" immediately after "Writing also helped", creating confusion about what exactly writing helped. BCA and ACB mix the phrases in ways that separate "to improve" from "the vocabulary", breaking a very common and strong collocation. None of these combinations produce a smooth or grammatically correct sentence.

Common Pitfalls:
A typical mistake in reordering questions is to focus only on local pairings of words and ignore the overall sentence pattern. Students may see "vocabulary, whether it was vernacular or English" and treat that unit as fixed, but they still must ensure that the earlier verbs and objects are in the right order. To succeed, always identify the main verb, base phrase and object, and then place descriptive or conditional clauses afterwards. Visualising how you would naturally write or say the idea in your own words can also guide you to the best arrangement.

Final Answer:
The most logical order of the segments is ABC, forming the sentence "Writing also helped to improve the vocabulary, whether it was vernacular or English".