Which of the Following Is Not a Lesson Learned for Studies

Which of the following is not a lesson learned for studies of the success and failure of different diversified financial services firm?

A) Diversification never works as a successful strategy.
B) Managing diversification is challenging especially with differences in business cultures, for instance an aggressive investment banking culture and a conservative traditional banking culture.
C) A large firm size doesn't always equate with efficiency, with some larger firms having difficulty exerting control over different divisions and having trouble with monitoring.
D) Without adequate risk management the benefits of diversification in terms of smoothing earnings and reducing risk can be lost.
E) Some customers may prefer financial services that are more specialized in different areas provided by niche financial institutions.