Which of the Following Statements Is Not True About the Constant

Which of the following statements is not true about the constant standard deviation condition of the linear regression model?

A) A residual plot can highlight the existence of a nonconstant standard deviation even when it is hard to see in the original scatterplot.
B) A QQ plot can help you determine whether the constant standard deviation condition holds.
C) A fan shape in a residual plot indicates that the constant standard deviation condition does not hold.
D) A constant standard deviation means that the vertical spread of the y- values about the line is the same across the entire line.