almost an identical question
https://gmatclub.com/forum/tom-bradley- ... 82416.html people could use those discussion also for clarity. almost both are same .
Tom Bradley was mayor of Los Angeles from 1973 to 1993, an era when the city had
transformed from a collection of suburban neighborhoods to the second-largest city in
the United States
.
A. an era when the city had transformed.
B. an era during which the city was transformed.
C. an era that transformed it.
D. during which era the city transformed.
E. during which the city was transformed
2. my doubt is
whether the following sentence is correct if the sentence is modified as follows,
Agatha Christie wrote some of her best works
in 1940,
during which many successful light-hearted whodunits were written