5. The method of value creation of the diversified corporate headquarters mainly includes three aspects, they are (    )

A． Entrusted by shareholders, using the property rights relationship as a link, to exercise the rights of shareholders through a single line of contact for diversified business, to play the role of this asset management center
B． Entrusted by shareholders to effectively manage the industry portfolio owned by them
C． Entrusted by shareholders to adjust the portfolio through industry entry and exit
D． Entrusted by shareholders to effectively manage the management team of subordinate enterprises
E．Entrusted by shareholders, using capital as a link to manage and control the financial resources of subordinate enterprises