According to the author, one can hardly achieve excellence unless one ______.

A．point out the role the workaholic plays in the American economy
B．defend people who are addicted to work
C．encourage us not to worry about our imperfection
D．consider the difficulties that confront us at middle age

A．who enjoy work more than anything else
B．who make greater contributions than others
C．who make uncommon sacrifice in their personal life
D．All of the above.