Choose the correct option (A, B, C or D) that best fits each space in the following passage

Everyone wants to reduce (17)______.  But    the     pollution problem is as complicated as it is (18) ______. It is complicated because (19) ______ pollution is caused by things that benefit people. For example, exhaust from automobile caused large percentage (20) _______ air pollution. But the automobile provides transportation to millions of people. (21) _______ discharge much of the material that pollutes air and water, but factories give employment to a large number of people. Thus, to end or greatly reduce pollutions (22) _______, people would have to stop using many things (23) _______  benefit them. Most people do not want to do that, of course. But pollution can be gradually reduces in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Government can pass and enforce laws that require businesses (24) _______ individuals to stop, or cut down on certain polluting activities.

 

Everyone wants to reduce (17)______.