In the following question, a sentence is given in direct speech. Out of the four alternatives, select the one which best expresses the same sentence in indirect speech for the question: "How old is your grandmother?", Navneet asked her.

Introduction / Context:
This question tests your understanding of changing a wh question from direct speech to indirect speech. The original sentence is a question about age, introduced by the reporting verb asked. When converting to indirect speech, you must consider word order, tense backshift, and pronoun changes. These small adjustments are essential for accurate reported speech in competitive exams.

Given Data / Assumptions:

• Direct sentence: "How old is your grandmother?", Navneet asked her.
• Reporting verb: asked, which introduces a question.
• Question word: How old, which remains in indirect speech.
• Pronoun your refers to the person being addressed by Navneet, that is, her.
• The original question uses present tense is for the verb be.

Concept / Approach:
When you convert a wh question to indirect speech, the question word (how, what, where and so on) stays, but the word order changes from question order to statement order. In reported speech with a past reporting verb like asked, present tense in the original direct speech usually changes to past tense in the reported clause. The auxiliary verb moves after the subject and pronouns may change to keep the meaning correct. So is becomes was and your becomes her in this context.

Step-by-Step Solution:
Step 1: Identify the reporting clause: Navneet asked her.Step 2: Take the question part How old is your grandmother and note that it is a wh question about age.Step 3: In indirect speech, keep the wh phrase How old at the beginning of the reported clause.Step 4: Change question word order to statement order by placing the subject before the verb: her grandmother was, not was her grandmother.Step 5: Backshift the tense because the reporting verb is in the past. Present tense is becomes past tense was.Step 6: Replace the second person pronoun your with her to match the object of the reporting verb.

Verification / Alternative check:
The final indirect sentence becomes: Navneet asked her how old her grandmother was. If we wanted to reconstruct the original direct question, we would move the verb before the subject and change the tense back to present: "How old is your grandmother?" This round trip demonstrates that the indirect version preserves the meaning and respects reported speech rules. The sentence sounds natural and grammatically correct in standard English.

Why Other Options Are Wrong:
Option A keeps the present tense is instead of changing it to was, ignoring the usual backshift with a past reporting verb, and is therefore considered incorrect in exam settings. Option B uses present perfect has been, which changes the meaning and is not supported by the original simple question. Option D keeps the original question word order how old is her grandmother even though it is inside an indirect clause, which is grammatically wrong because indirect wh clauses use statement order, not question order.

Common Pitfalls:
Many learners forget to change the word order and simply insert the question as it is after the reporting verb, which leads to errors like Option D. Others ignore tense backshift and leave is instead of was, or they change the tense unnecessarily to more complex forms like has been. To avoid these mistakes, remember three key points: keep the wh word; use subject plus verb order in the reported clause; and, when the reporting verb is in the past, usually shift present to past. Checking these steps will help you reach the correct indirect speech form consistently.

Final Answer:
The correct indirect speech sentence is Navneet asked her how old her grandmother was.