Estimation Is Best Defined As

Estimation is best defined as:

A) a process of inferring the values of unknown population parameters from those of known sample statistics
B) a process of inferring the values of unknown samples statistics from those of known population parameters
C) any procedure that views the parameter being estimated not as a constant, but, just like the estimator, as a random variable
D) a sampling procedure that matches each unit from population A with a "twin" from population B so that any sample observation about a unit in population A automatically yields an associated observation about a unit in population B
E) both a process of inferring the values of unknown samples statistics from those of known population parameters and any procedure that views the parameter being estimated not as a constant, but, just like the estimator, as a random variable