. options granted vested upon the earlier to occur of ( a ) the exercise by or on behalf of mr . gearon of his right to sell his interest in atc south america to the company , ( b ) the exercise by the company of its right to acquire mr . gearon 2019s interest in atc south america , or ( c ) july 1 , 2006 . these options expired ten years from the date of grant . in october 2005 , in connection with the exercise by mr