Studies have shown that the more high-stress points a bridge has, the more likely it is to fracture eventually. This might lead one to expect fractures to develop at high-stress points. Surprisingly, however, fractures develop not at high-stress points but elsewhere on the bridge. Which one of the following, if true, contributes most to an explanation of why bridges fracture elsewhere than at high-stress points? ['Structures with no high-stress points can nonetheless have a high probability of fracturing.', 'Fractures do not develop at high-stress points, because bridges are reinforced at those points; however, stress is transferred to other points on the bridge where it causes fractures.', 'In many structures, the process of fracturing often causes high-stress points to develop.', 'In many structures other than bridges, such as ship hulls and airplane bodies, fractures do not develop at high-stress points.']