Select the most appropriate option to fill in the blank

Select the most appropriate option to fill in the blank.

Scarcely had my mother left the room_______the children started making noise.

A.            Then

B.            Than

C.            When

D.            That

 Sol:

Option c is the most appropriate word to fill the blank here, ‘when’ is used with ‘scarcely/hardly’ and ‘than’ is used with ‘no sooner’, and inversion is used in all these cases.