【求助】请问standard of 与standard for 的区别是？

melodiesoflife

37. GWD25-Q37.
Though the law will require emissions testing of all diesel vehicles, from tractor trailers to excursion buses, it will have no effect on sport utility vehicles, almost all of which are gasoline powered, and will not be subjected to emissions-control standards as stringent as they are for diesel-powered vehicles.
A.    powered, and will not be subjected to emissions-control standards as stringent as they are for
B.    powered, and therefore not subjected to emissions-control standards that are as stringent as those of
C.    powered and therefore not subject to emissions-control standards as stringent as those for
D.    powered, which are not subject to emissions-control standards as stringent as they are for
E.    powered and therefore they are not subject to emissions-control standards as stringent as those of

答案C。请问standard of 与standard for 的区别是？谢谢~

kate198501