Which of the Following Statements Are Correct

Which of the following statements are correct? $\begin{array}{|l|l|}\hline A&\text { If there are two unbiased estimators of a parameter, the one whose variance is larger is said to}\\&\text { be relatively efficient.}\\\hline B&\text { If there are two unbiased estimators of a parameter, the one whose mean is larger}\\&\text {is said to be relatively efficient. }\\\hline C&\text {If there are two unbiased estimators of a parameter, the one whose mean is smaller is }\\&\text { said to be rel atively efficient.}\\\hline D&\text { If there are two unbiased estimators of a parameter, the one whose variance is smaller is said }\\&\text {to be relatively efficient. }\\\hline \end{array}$