(B) The pollution may have been reduced to a level at which the salmon can survive.
(C) Oxygen starvation is often a consequence of pollution, and this may have killed the salmon.
(D) The salmon may have been killed by one particular pollutant, which has now been removed while others remain.
(E) There may still be pollution, but its nature may have changed to a form that saimon can tolerate.
4.The state’s licensing procedures for day-care providers are inadequate.used to leave my son with a wonderful woman who kept a group of neighborhood children, but she quit rather than put up with the licensing paperwork. And a friend of mine tells me that he cannot recommend the day-care center that he uses, even though it is licensed, because the care providers are not interested in doing anything beyond meeting the minimum requirments of health and safety.
The author of the passage argues by
(A) providing examples to support two opposing positions
(B) basing a conciusion on specific cases