John scores 93 on this year's AHSME. Had the old scoring system still been in effect, he would score only 84 for the same answers. How many questions does he leave unanswered? (In the new scoring system one receives 5 points for correct answers, 0 points for wrong answers, and 2 points for unanswered questions. In the old system, one started with 30 points, received 4 more for each correct answer, lost one point for each wrong answer, and neither gained nor lost points for unanswered questions. There are 30 questions in the 1986 AHSME.)<spanclass=′latex−bold′>(A)</span>6<spanclass=′latex−bold′>(B)</span>9<spanclass=′latex−bold′>(C)</span>11<spanclass=′latex−bold′>(D)</span>14<spanclass=′latex−bold′>(E)</span>Not uniquely determined