Annie28 wrote:
In order to better differentiate its product from generic brands, the cereal company first hired a marketing firm that specializes in creating campaigns to build brand awareness and then retools its factory to produce a variety of different shapes of cereal.
(A) then retools its factory to produce a variety of different shapes of cereal
(B) retools its factory to produce a variety of different shapes of cereal
(C) then retooled its factory to produce a variety of different shapes
...
(A) then retools its factory to produce a variety of different shapes of cereal
(B) retools its factory to produce a variety of different shapes of cereal
(C) then retooled its factory to produce a variety of different shapes
...
