Tough SC but I answered correctly although my logic is rather questionable.
A) predicted that, just as the growth of democracy has generally followed industrial development in other nations, democratic institutions will soon flourish
"growth of democracy followed...." vs "democratic institutions ...flourish" => not parallel.
B) predicted, just as democracy has generally grown following other nations' industrial development, that democratic institutions will soon flourish
"democracy...grown" vs "democratic institutions...flourish" => ok
C) predicted, just as the growth of democracy generally following industrial development in other nations, that democratic institutions will soon be flourishing
"just as"..."that" is unidiomatic.
"the growth of...following" vs "democratic institutions ... be flourishing"
"just as" is used for comparing actions. In C, compared phrase is not complete S-V.
D) predicted that, just as democracy has generally grown after other nations' industrial development, that democratic institutions will soon be flourishing
"just as democracy ...grown" vs "that democratic institutions ...be flourishing" not parallel.
E) been predicting that, just as the general growth of democracy following other nations' industrial development, democratic institutions will soon flourish
We don't need to underline duration of predicting so Present Perfect Continuous is wrong.
"growth of democracy following" vs "democratic institutions ...flourish" - not parallel.