Which of the following is true of the American car culture of the 1950s and 1960s?

a. The growing reliance on automobiles permanently changed American culture.
b. It led to the creation of the US Highway System, marked by the iconic black-and-white shields and composed almost exclusively of two-lane roads.
c. Americans owned more cars per person and drove more miles than ever before.
d. These decades were defnitively the age of the automobile, more than any other single era in American history.