In this reported speech question, the direct sentence is He said, "They will be using my car for the trip", and you must choose the indirect form that correctly reports this statement with appropriate changes to pronouns and the future form. Select the option that best preserves the original meaning in reported speech.

Introduction / Context:
This question focuses on converting a direct statement in the future continuous tense into reported speech. The speaker says, They will be using my car for the trip. In reported speech, the future form will be using normally changes to would be using when the reporting verb is in the past. In addition, the possessive pronoun my, which refers to the speaker, usually becomes his in indirect speech when the speaker is referred to in the third person as he.

Given Data / Assumptions:

• Direct speech: He said, "They will be using my car for the trip".
• Reporting verb is said in the simple past.
• The reported clause uses future continuous: will be using.
• The possessive my refers to the speaker, who is identified as he in the reporting clause.

Concept / Approach:
When converting future forms in direct speech to reported speech with a past reporting verb, will normally changes to would. Thus will be using becomes would be using. Pronouns and possessives must also be adjusted to reflect the perspective of the reporter: my becomes his if the speaker is a male referred to as he. The subject they remains they, as it still refers to the same group. Therefore, the most accurate reported sentence will say that they would be using his car for the trip.

Step-by-Step Solution:
First, identify the reporting clause He said and the reported clause They will be using my car for the trip. Second, change will be using to would be using because the reporting verb is in the past, which calls for backshift of the future tense. Third, convert the possessive my to his, since the speaker is referred to as he and my car refers to his own car. Fourth, introduce the reported clause with that to form He said that they would be using his car for the trip. Fifth, check that all pronouns and verb forms now reflect the correct point of view and time relationship.

Verification / Alternative check:
To confirm, convert the candidate indirect sentence back to direct speech. From He said that they would be using his car for the trip we can reconstruct He said, "They will be using my car for the trip". Here, would be using becomes will be using, and his car becomes my car. This process returns us to the original direct sentence, which indicates that the indirect form is correct.

Why Other Options Are Wrong:
Option A, He said that they would be using my car for the trip, fails to change my to his, so the pronoun still reflects the speaker's immediate viewpoint and not the third person reporting perspective.

Option C, He said that we will be using his car for the trip, changes the subject from they to we and does not shift will to would, which alters both the participants and the time reference.

Option D, He said that they will be using my car for the trip, keeps both will and my, ignoring the usual tense backshift and pronoun change required in reported speech with a past reporting verb.

Common Pitfalls:
Learners often forget to change future forms when reporting from a past viewpoint, leaving will unchanged instead of converting it to would. Another common difficulty is correctly changing personal and possessive pronouns, especially my and your, which must be interpreted relative to the original speaker and listener. Careful attention to these shifts is necessary to produce accurate reported speech in examinations.

Final Answer:
The correct indirect sentence that applies both tense and pronoun changes properly is He said that they would be using his car for the trip.