Concept:The sentence has an error in the part where the verb form does not fit the structure.Explanation:Part (3) says “eight flights, includes two international flights”.After a comma, the correct form is the participle “including”, not the finite verb “includes”.It should read: “eight flights, including two international flights”.Parts (1), (2), and (4) are grammatically correct.Therefore, the error is in part (3).Answer:Option C, part (3), is correct.