A financial management firm has existed for more than $70$ years. Some of its original clients' grandchildren are now clients of the firm themselves. The partners and staff of the firm have spent most or all of their careers with the firm. Many have even married into each other's families. This firm has capabilities that would be costly to imitate primarily because of its:

a$.$ unique historical conditions. b$.$ access to large amounts of financial capital. c$.$ causally ambiguous core competencies. d$.$ social complexity