Which of the Following Assumptions Is Known as Exclusion Restrictions

Which of the following assumptions is known as exclusion restrictions?

A) The assumption that an instrumental variable is excluded from a regression model and is correlated with the error term.
B) The assumption that an instrumental variable is excluded from a regression model and is correlated with an exogenous explanatory variable.
C) The assumption that an exogenous explanatory variable is excluded from a regression model and is uncorrelated with the error term.
D) The assumption that an endogenous explanatory variable excluded from a regression model and is uncorrelated with the error term.