Among fatal plane crashes that occurred during the past 70 years, 503 were due to pilot error, 90 were due to other human error, 326 were due to weather, 382 were due to mechanical problems, and 643 were due to sabotage. Construct the relative frequency distribution. What is the most serious threat to aviation safety, and can anything be done about it? Complete the relative frequency distribution below. Relative Frequency 25.9% 4.6% 16.8% Cause Pilot error Other human error Weather Mechanical problems 19.7 % Sabotage 33.1% (Round to one decimal place as needed.) What is the most serious threat to aviation safety, and can anything be done about it? A. Sabotage is the most serious threat to aviation safety. Airport security could be increased. B. Mechanical problems are the most serious threat to aviation safety. New planes could be better engineered. C. Weather is the most serious threat to aviation safety. Weather monitoring systems could be improved. D. Pilot error is the most serious threat to aviation safety. Pilots could be better trained.