Which of the Following Best Describes an Unbiased Estimator

Short Answer

Which of the following best describes an unbiased estimator? $\begin{array}{|l|l|}\hline A&\text {Every estimator is an unbiased estimator. }\\\hline B&\text {An interval estimator is an unbiased estimator. }\\\hline C&\text {An unbiased estimator of a population parameter is an estimator whose expected value is }\\&\text { equal to that parameter.}\\\hline D&\text { None of these choices are correct.}\\\hline \end{array}$