A new client with no other investment assets has just come into an inheritance of $500,000 of ABCD stock, a blue chip company listed on the NYSE. As the adviser to this customer, your IMMEDIATE concern should be:
A. whether the company is a candidate for delisting
B. the possibility that the value of ABCD stock may decline sharply
C. the lack of diversification of the customer's investment
D. whether the customer paid any estate tax liability due