As soon as the teacher enters the classroom, the students stand up.(Negative)

As soon as the teacher enters the classroom, the students stand up.(Negative)

• ক. No sooner does the teacher enter the classroom than the students stand up.
• খ. No sooner the teacher enters the classroom than students stand up.
• গ. No sooner had the teacher enterd the classroom than the students stood up.
• ঘ. The students stood up as the teacher entered the classroom.