Which of the Following Statements Is True About Investments in General

Which of the following statements is true about investments in general and specific human capital?

A) Firms invest in development of general human capital of their employees.
B) Employees invest in gaining specific human capital.
C) Investment in general human capital of its employees by a firm may turn into a sunk cost if the employee leaves the organization to join another after completing the relevant training.
D) When a firm invests in specific human capital of its employees, the employees become more attractive to other firms whose workplaces are operated and staffed differently.