Choose the grammatically correct sentences from the options below:-(A…

The correct answer is Option (1) → (B) and (D) only

Note: The given answer is as per the official NTA Answer Key. However, sentences (A) and (C) are not grammatically wrong in every context; (B) and (D) are the two sentences that show the time relation between the two past actions correctly and naturally on their own, as explained below.

Clue word: when — the tense in the "when" clause shows how the manager's talk was related in time to his arrival.

(A) He reached the office when the manager spoke to the client. — Less appropriate. Two simple past verbs joined by "when" make the two actions happen one after the other: the manager began speaking as he arrived. The sentence is grammatical, but it does not show the talk as a background action.

(B) He reached the office when the manager was speaking to the client. — Correct. The past continuous "was speaking" shows an action in progress when the shorter action "reached" took place.

(C) He reached the office when the manager had been speaking to the client. — Less appropriate. The past perfect continuous shows an action that had been going on for some time before another past action. A time phrase (for an hour, since morning) is not compulsory, but without one or a wider context the sentence sounds less natural than (B).

(D) He reached the office when the manager had just finished speaking to the client. — Correct. The past perfect "had just finished" shows that the manager's talk was completed just before he reached the office.

Contrast: "was speaking" means the talk was in progress when he arrived; "had just finished" means it was over just before he arrived.