IMO C - Took me 2 mins. Not that sure here. Tricky question ...for me..
A) A comic book industry giant, sued an animation studio
soon after the production of a movie which plagiarized these characters ended. - No issues as such in this sentence , the time marker Soon After the production perfectly denotes the timing between the two actions, but i think C shows the meaning correctly. Why would they wait for the production to end ?
(B) had sued an animation studio soon after the production of a movie which plagiarized these characters ended - There are no two actions happening in the past. And if he had sued the animation studio then why did the production end ? it should have stopped in the middle...
(C)
had sued an animation studio
before the production of a movie which plagiarized these characters
ended - Before the production ended the company had sued ... Now this clears the meaning issue which was present in A .. The Comic book industry Giant had sued the studio before the production of the movie ended.... And thats how they prevented the movie from being released....
(D) sued an animation studio soon after the production of a movie which plagiarized these characters had ended ---Meaning error and tense error.
(E) has sued an animation studio soon after the production of a movie which plagiarized these characters was over - Not the right tense no need to have present perfect here. The action doesnt start in the past and continues in the present.