Which of the following statements BEST explains how command economies have changed over time? A. Command economies have failed immediately when attempted. B. Command economies have become more common since 1986. C. Command economies have experienced some success, but have declined economically. D. Command economies have completely succeeded each time they have been used.

How does the supremacy clause of the u.s. constitution affect the states? o a. it requires each state to establish a supreme court. b. it declares that the federal government can take away state powers if necessary. o c. it allows state governments to overthrow the federal government if necessary. o d. it ensures that the u.s. constitution overrules each state constitution