One of the Properties of the OLS Estimator Is
A)X $\hat \beta$

Multiple Choice

One of the properties of the OLS estimator is

A) X $\hat \beta$ = 0_k+1.
B) that the coefficient vector $\hat \beta$ has full rank.
C) $X ^ { \prime }$ (Y - X $\hat \beta$ ) = 0_k+1.
D) ( $X ^ { \prime }$ X) ^-1= $X ^ { \prime }$ Y