Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Throughout the life of the fish, its electric discharges vary in power from undetectable to fairly potent. B. Nearly continuous discharges undetectable by humans create a stable, low-level electric field around the body of the fish. C. Human handlers cannot feel the electric discharges because the discharges are at such low power levels. D. The discharges are so weak that they would have to be fired almost continuously to create a detectable electric field.