The Following Graphic Is Adapted from One in Wainer (1984)

Multiple Choice

The following graphic is adapted from one in Wainer (1984) , plotting the number of private and public elementary schools (in thousands) in the U.S. between 1930 and 1970. Wainer was presenting it as a bad example, and I have made it worse. What is bad about this example?

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A) The three dimensional effect only makes the graph harder to read.
B) Any change in the number of private schools is difficult to see.
C) The time intervals on the abscissa are too broad.
D) a and b but not c