Concept:When converting a WH-question (starting with how, what, etc.) from direct to indirect speech, the reporting verb changes to "asked", no conjunction like "that" is used, and the tense shifts to past. The word order also changes from question form to statement form.
Explanation:The direct speech is: "I said to the teacher, 'How many students are there in the school?'"
First, change the reporting verb "said to" to "asked" because the sentence is a question.
In WH-questions, the WH-word itself acts as the connector; therefore, no extra conjunction like "that" or "whether" is needed.
Next, change the present tense "are" to past tense "were" to match the past reporting verb "said".
Also, rearrange the words: the interrogative order "are there" becomes the statement order "there were".
Now check the options:
Option A uses "that" before "how" – this is incorrect because "that" cannot be used with a WH-word.
Option C uses "whether" – this is only for Yes/No questions and changes the meaning.
Option D keeps "are" in present tense – incorrect because the tense must change to past.
Only Option B follows all rules correctly.
Answer:I asked the teacher how many students were there in the school. (Option B)