3.
Your Answer is
Correct Answer is C
Explanation
According to the meaning of the sentence "Porterfield concludes that if he opened a theater in Virginia to accept food as a ticket, his actors can often have food", we know that the underlined part and the sentence guided by if constitute the main clause.
Item C: then as an adverb expresses the sequence of actions of the main clause.
Item A/B: The underlined part does not need the master-slave conjunction so or while, and item A/B is wrong.
Item D: The comparison of the than table is used here for semantic errors.