Which of the following if true, most seriously weakens the argument? A. Burying power lines and other measures to protect the public from such electromagnetic fields would be prohibitively expensive. B. Telephone line workers are exposed to levels of chemical solvents high enough to cause brain cancer. C. High exposure to strong electromagnetic fields is correlated with a slightly higher-than-normal incidence of childhood leukemia, which is a form of cancer. D. Public health officials who found that a group of different illnesses in people living near a power substation could not reliably be attributed to its electromagnetic field were accused of covering up the facts. E. Telephone line workers, like most people. have electrical appliances at home, and most electrical appliances, when turned on, are surrounded by and electromagnetic field of some measurable level.