Each year companies in the United States could save as much as $58 billion annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided offices with cleaner air.
(A) annually by preventing illness among employees and gain as much as $200 billion through improving performance of workers if they simply provided
(B) annually if they prevented employee illness and gain as much as $200 billion through worker performance improved by simply providing
(C) annually in employee illness prevention and gain as much as $200 billion through worker performance improved by simply providing
(D) in employee illness prevention and gain as much as $200 billion through improving performance of workers if they simply provided
(E) by preventing illness among employees and gain as much as $200 billion through improved worker performance if they simply provided
原文意思：
每年美国的公司能通过预防员工生病节省一部分钱并且能通过提高员工战斗力挣一些钱。