Over the past two years, legislators have been revising environmental regulations and creating new restrictions that are increasingly difficult for companies to circumvent them.
IMO E
A. legislators have been revising environmental regulations and creating new restrictions that are increasingly difficult for companies to circumvent
them --> them is not needed, what is it referring to companies or restrictions
B. legislators have revised environmental regulations and created new restrictions that are increasingly difficult for companies circumventing
them --> them is not needed , what is it referring to companies or restrictions
C. legislators are revising environmental regulations and creating new restrictions that are increasingly difficult for companies to circumvent --> Tense error. Making it present continuous implying it is happening currently.
D. while legislators have been revising environmental regulations and creating new restrictions, it is increasingly difficult for companies to circumvent them---> While is not needed. Again Them is extra --> what is it referring to companies or restrictions
E. legislators have revised environmental regulations and created new restrictions that are increasingly difficult for companies to circumvent---> Tense is correct , Them is removed .