Which Statement(s)concerning SO_x and NO_x Emissions Are True

Which statement(s) concerning SO_x and NO_x emissions are true?
I.Automobiles produce NO_x but very little SO_x.
II.Power plants produce only SO_x.
III.Diesel powered vehicles produce only SO_x.
IV.The high concentration of nitrogen compounds in gasoline accounts for the formation of NO_x by automobiles and trucks.

A) I only
B) I and II only
C) II and IV only
D) I,II,III,and IV