The correct option is C man
Option B is the correct answer. Man is being talked about in the sentence, also valid with the use of the following verb could establishing that it does the work in the sentence. Thus, man is the subject in the sentence. Option A is the adverbial clause of time setting up the timeline for the events mentioned in the film. Options C and D are objects to the verb could attribute and the preposition to, respectively. Thus, Options A,C and D are all incorrect.