Based on data collected from policyholders, life insurance companies have developed tables that list standard weight ranges for various heights. Policyholders whose weight fell within the range given for their height lived longer than those whose weight fell outside their given range. Ttherefore, if people whose weight falls outside their given range modified their weight to fall within that range, their overall life expectancies would improve. Which one of the following is an assumption on which the argument relies?
A: Holders of life insurance policies do not have longer overall life expectancies than the general population.
B: Some people would be unwilling to modify their weights solely to increase the general population's overall life expectancies.
C: The tables include data gathered from policyholders whose deaths resulted from accidents in addition to those whose deaths resulted from natural causes.
D: People's efforts to modify their weight to conform to a given range would not damage their health enough to decrease their overall life expectancies.
Choose A, B, C or D as your solution.
D