In the following question, a sentence is given in direct speech. Select the option that best expresses the same sentence in indirect (reported) speech. He said, "I started the job today."

Introduction / Context:
This question checks how to report a simple past action linked with the time word "today". The speaker refers to an action that happened earlier the same day. When this is reported later, both the tense and the time expression must be adapted. The goal is to show that the job had already started before the time of reporting, and that the original reference to "today" now becomes "that day".

Given Data / Assumptions:

• Reporting verb: "said" in simple past.
• Direct speech: "I started the job today."
• Pronoun "I" refers to "he" in the reported sentence.
• Verb "started" is in simple past.
• Time expression "today" is relative to the original moment of speaking.

Concept / Approach:
With a past reporting verb, simple past usually changes to past perfect in reported speech to show that the action was completed before the time of reporting. Time expressions also need adjustment; "today" changes to "that day". Pronoun "I" must change to "he" to match the third person perspective. No question or command is involved, so the structure remains a simple statement with conjunction "that" introducing the reported clause.

Step-by-Step Solution:
Step 1: Start the reported sentence with "He said that". Step 2: Change "I started" to "he had started". This backshifts simple past to past perfect and changes the pronoun correctly. Step 3: Replace "today" with "that day" to represent the time of the action relative to the time of reporting. Step 4: The complete reported sentence becomes "He said that he had started the job that day."

Verification / Alternative check:
The reported version clearly indicates that starting the job happened before the reporting moment, which fits real life communication. The phrase "that day" tells the reader that the job was started earlier on the same calendar day when the original words were spoken. The sentence structure is correct and follows standard rules for reporting simple statements with time expressions.

Why Other Options Are Wrong:
Option A keeps "has started" and "today". Present perfect "has started" is not suitable when the reporting verb is in past tense, and "today" should change to "that day". Option C uses "had had started", which is not a correct tense structure in this context. Option D repeats the same incorrect double perfect with "has had started", combining two unnecessary auxiliary verbs and also keeping the wrong tense sequence.

Common Pitfalls:
Learners may mistakenly think simple past should remain unchanged after a past reporting verb, especially when the action and the reporting seem close in time. Another frequent error is to overlook small time words, leaving "today" unchanged. Always identify the tense in the original quote, then decide on the proper backshift, and finally examine all time markers and pronouns. This disciplined approach ensures accurate reported speech.

Final Answer:
The correct reported sentence is He said that he had started the job that day.