A researcher wants to study what affects a person's understanding of symbolic logic. He states: "We define 'understanding of symbolic logic' as the ability of correct reasoning, especially regarding making inferences." With this statement, the researcher
A) defines the moderator
B) defines the dependent variable
C) conceptualizes "understanding of symbolic logic"
D) operationalizes "understanding of symbolic logic"
E) highlights that the idea of "symbolic logic" is socially constructed