Based on the residual plot below, you will conclude that there might be a violation of which of the following assumptions:

a Mean of errors equals to zero

b Normality of errors

c Constant variance of errors

d Independence of errors

Residuals 6000 4000 2000 0 -2000 -4000 00 Footage Residual Plot 1,000 2,000 3,000 4,000 5,000 6,000 Footage