Concept:The correct way to join two sequential past events using the correlative conjunction “no sooner…than”.
Explanation:The two sentences describe two events happening in quick succession in the past.
The first event is “The teacher entered the classroom.”
The second event is “All the students stopped talking.”
The conjunction “no sooner…than” is used to show that the second event happened immediately after the first.
The structure requires an inverted auxiliary after “no sooner” and a simple past tense verb.
The correct form is: “No sooner did the teacher enter the classroom than all the students stopped talking.”
Option A matches this structure exactly.
Option B changes the meaning by adding “were asked”.
Option C uses the present tense “enters”, which is incorrect because the original sentences are in past tense.
Option D reverses the order of events, which is not what the original sentences convey.
Answer:Option A: No sooner did the teacher enter the classroom than all the students stopped talking.