题目选项分析

The Ergonomic Society conducted a study that indicated that many people develop severe back problems during adulthood, and that virtually all such people who received chiropractic treatment showed great improvement. Therefore, in order to minimize the proportion of the population that suffers from back pain, the Ergonomic Society recommended that chiropractic treatment be directed toward those adults who suffer from severe back problems.

Which of the following is an assumption on which the argument depends?

【选项】Large insurance carriers cover chiropractic care for back problems to a lesser degree than they do other medical treatments.