Which One of the Following Statements Regarding Employee Stock Options

Which one of the following statements regarding employee stock options (ESOs) is correct?

A) ESOs grant an employee the right to buy a fixed number of shares of company stock at the market price.
B) Employees must exercise their ESOs prior to those ESOs becoming vested.
C) Employees may forfeit their ESOs if they terminate their employment with the issuing firm.
D) If a firm issues ESOs it must make them available to all employees.
E) Employees can sell their ESOs if they do not want to personally exercise them.