In an examination, a student scores 3 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts all 120 questions and secures 180 marks, the number of questions he attempts correctly, is:  Choose the correct choice from the following: A) 45 B) 90 C) 80 D) 75 E) 70

Rationale: "let the number of correct answers be x . number of incorrect answers = ( 120 â € “ x ) . 3 x â € “ ( 120 â € “ x ) = 180 or 4 x = 300 or x = 75 answer : d"
Answer: D