During Requirements Structuring

During requirements structuring:

A) an E-R model represents conceptual data requirements for a particular system
B) the conceptual E-R data model is refined before it is translated into a logical format from which database definition and physical database design are done
C) an enterprise-wide data model with very broad categories of data and little detail is prepared
D) a specific E-R model is built to help explain the scope of a particular systems analysis and design effort