A person is more likely to become disabled as that person ages. Among adults in the country of East Wendell, however, the proportion receiving disability benefit payments shrinks from 4 percent among 55 to 64 year olds to 2 percent for those aged 65 to 74 and 1 percent for those aged 75 and older. The explanation of this discrepancy is that the proportion of jobs offering such a disability benefit has greatly increased in recent years. Which one of the following, if true about East Wendell, shows that the explanation above is at best incomplete? ['The treatment of newly incurred disabilities is more successful now than in the past in restoring partial function in the affected area within six months.', "Under most employers' plans, disability benefit payments stop when an employee with a disability reaches the usual retirement age of 65.", 'Medical advances have prolonged the average lifespan beyond what it was 20 years ago.', 'For persons receiving disability benefit payments, those payments on average represent a smaller share of their predisability income now than was the case 20 years ago.']