The given sentence is divided into four segments. Identify the segment that contains a grammatical error.
When I returned to the office, / no work was left / as my friend Rahul / has done everything.

Correct option is D

Option (d) contains an error.
Explanation: The sentence is in the past tense, as indicated by the phrase "When I returned to the office".
Therefore, to maintain proper sequence of tenses, the verb "has done" (present perfect tense) should be changed to "had done" (past perfect tense), because it refers to an action completed before the time the speaker returned.
Correct sentence: When I returned to the office, no work was left as my friend Rahul had done everything.
Grammatical rule used:
· When expressing two past actions, use past perfect for the action that happened first and simple past for the action that happened later.
· Present perfect tense ("has done") is not used to describe actions completed before a point in the past.
Example:
· Incorrect: When I arrived, he has eaten dinner.
· Correct: When I arrived, he had eaten dinner.