Answer:
C. heteroscedasticity
Explanation:
The OLS regression assumption of error variance being constant irrespective of independent variables, is called Homoscedasticity.
Var (u | x) = σ^2 (u) ;
where u = error term, x = independent variable, σ^2 (u) = constant error variance
The violance of this assumption ie Var (u | x) is related to independent variable x, is called Heteroscedasticity.