Choose the correct form of the question sentence: What your Sirname is?

Introduction / Context:
This question checks your understanding of word order and spelling in English interrogative sentences. The original sentence What your Sirname is? is incorrect in two ways. The task is to identify the choice that corrects both the grammar and the spelling to form a natural English question. This type of correction question appears frequently in competitive exams and helps you practise standard patterns.

Given Data / Assumptions:

• The original incorrect form is What your Sirname is?
• We need a correct English question that asks about a person family name.
• The auxiliary verb is must come before the subject in a normal wh question.
• The correct spelling of the word is surname, not sirname.

Concept / Approach:
In English, a wh question that asks for information uses the pattern question word plus auxiliary verb plus subject plus main verb. When asking for someone surname, the common form is What is your surname? Here, what is the question word, is is the verb, your is the possessive determiner, and surname is the noun. The original sentence places is at the end and spells the noun incorrectly. Among the options, only option B fixes both issues by placing is before your and using the correct spelling surname.

Step-by-Step Solution:
Step 1: Identify the intended meaning of the sentence, which is to ask for someone family name.Step 2: Recall the standard pattern for such questions: What is your name or What is your surname.Step 3: Examine option B What is your surname? This matches the pattern wh word plus verb plus subject plus complement, and surname is spelled correctly.Step 4: Examine option A What your Sirname? This still lacks the verb is and keeps the incorrect spelling Sirname.Step 5: Examine option C Your surname is what? which can be used in spoken English for emphasis but sounds less natural as a neutral question, and the question stem is clearly guiding toward the standard form. Therefore option B is the best correction.

Verification / Alternative check:
We can test the naturalness of each option. English learners are usually taught to say What is your name? in early lessons. Extending that pattern gives What is your surname? for asking the family name. Other forms like Your surname is what? are sometimes used for surprise or emphasis but are not the base pattern for neutral questions. In written exams, the expected answer is almost always the neutral standard form, which supports choosing option B.

Why Other Options Are Wrong:
Option A omits the verb is, making the sentence fragmentary, and misspells surname as Sirname. Option C uses a less common word order that sounds like repetition of information rather than a direct polite question. Option D none of the above cannot be correct because we have already identified a fully grammatical and natural option among the choices. Thus only option B satisfies all requirements.

Common Pitfalls:
Many learners carry over word order from their first language and place the verb at the end of the question, as in What your name is? This pattern is incorrect in standard English. Another pitfall is the incorrect spelling sirname, which appears in some informal contexts but is not accepted in exams. Always remember the structure What is your plus name or surname and spell surname with sur, not sir.

Final Answer:
The correct and natural English question is What is your surname? so option B is correct.