Half a dozen Q40 airliners have crashed in the past two years. The manufacturer has countered claims that the Q40' s design is faulty by pointing out that, in each of the accidents, investigations indicated pilot error as the cause. Which of the following, if true, provides the strongest support for the manufacturer's position? ['One of the crashes occurred in very poor visibility when the pilot was attempting to land.', "In four of the crashes, the pilot's error involved disregarding instructions or information supplied by air-traffic control", 'Each of the investigations identified several factors other than pilot error as subsidiary causes.', 'Like most modern airliners, the Q40 was designed with the goal that it should be highly tolerant of pilot error.']