Less than 10 percent of the world's people, and of the participants in combat sports worldwide, are left-handed. However, a majority of top-level competitors in combat sports worldwide are left-handed. Which of the following, if true, most helps to resolve the discrepancy presented in the passage? ['A significant number of left-handed competitors in combat sports have trained under coaches who have forced them to fight from right-handed positions and angles.', 'Left-handedness is more common in primitive cultures with high rates of death by violence than in other primitive cultures.', 'Because left-handedness is so rare, opponents of left-handed fighters are ill equipped to handle the positions and angles from which those fighters attack.', 'Among top-level competitors in many non-combat sports, such as tennis and baseball, left-handedness is also much more common than in the general population.']