Which of the Following Has Been Identified as a Problem

Which of the following has been identified as a problem with mentoring?

A) Women executives are reluctant to serve as mentors either to other women or to men because they themselves received little help.
B) The proportion of racial and ethnic minorities holding senior management positions is low.
C) The relationship between mentor and protégé is frequently marked by a "break-up" when the protege advances in the hierarchy.
D) The most successful managers are too busy to be effective mentors, so junior managers are often mentored by less-talented senior managers.