The lawyer said to them, "Call the witness." Choose the option that best expresses this sentence in indirect speech.

Introduction / Context:
This question checks your understanding of converting direct speech to indirect (reported) speech when the original sentence is an imperative command. The direct speech is a clear instruction from the lawyer to them. In indirect speech, we need to change both the reporting verb and the structure of the reported clause to reflect a command or order rather than a simple statement or question.

Given Data / Assumptions:

• Direct speech: The lawyer said to them, "Call the witness."
• The reporting verb is said to them and the quoted part is an imperative without a subject.
• The sentence is a command, not a request or a question.
• Indirect commands usually use verbs like told, ordered, or commanded followed by an infinitive (to + verb).

Concept / Approach:
When changing a command from direct to indirect speech, we generally replace said to with a verb that indicates the type of command, such as ordered, instructed, or commanded. The imperative form Call the witness becomes an infinitive phrase to call the witness. The pronoun them remains the object receiving the command. Therefore, the structure The lawyer commanded them to call the witness correctly expresses both the original meaning and the command form.

Step-by-Step Solution:
Step 1: Identify the nature of the quoted sentence. Call the witness is an imperative, expressing an order.Step 2: Replace said to them with a suitable reporting verb that indicates a command. Commanded them or ordered them are both appropriate.Step 3: Convert the imperative verb call into the infinitive to call for indirect speech.Step 4: Keep the object the witness unchanged, since there is no shift in person needed.Step 5: Combine these pieces to form: The lawyer commanded them to call the witness.

Verification / Alternative check:
Check each option against the rules. The lawyer asked for the witness changes the structure incorrectly and removes the idea that they had to perform the action of calling; it also sounds like a request rather than a direct command to them. The witness be called by the lawyer is an incomplete and awkward passive, and it suggests that the lawyer will call the witness, which is not the original meaning. The lawyer called the witness changes the tense and content completely; it now describes an action performed by the lawyer, not an order given. The lawyer commanded them to call the witness preserves the command and the roles correctly.

Why Other Options Are Wrong:
Option A uses asked for, which implies that the lawyer simply requested the presence of the witness, not that he told them to call the witness. Option B is grammatically incomplete and misplaces the subject in a passive construction. Option C indicates a past action by the lawyer rather than an instruction to others. None of these maintain the imperative meaning and correct reporting structure.

Common Pitfalls:
Learners sometimes forget to change the reporting verb when converting commands and leave said instead of using told, ordered, or commanded. Another common error is to turn the imperative into a that-clause instead of an infinitive, leading to unnatural sentences. Remember that for commands, the pattern is usually subject + reporting verb + object + to + base verb.

Final Answer:
The correct indirect speech form is The lawyer commanded them to call the witness., so option D is correct.