When Autocorrelation Is Present, One of the Assumptions of the Regression

When autocorrelation is present, one of the assumptions of the regression model is violated and that assumption is?

A) ?the expected value of the error term $\Sigma$ is zero.
B) ?the variance of the error term $\Sigma$ is the same for all values of x.
C) ?the values of the error term $\Sigma$ are independent.
D) ?the values of the error term $\Sigma$ are normally distributed for all values of x.