Many share-based compensation awards, accounted for under ASC 718, 'Compensation Stock Compensation', include one or more conditions in order for the recipient to "earn" the award. Of the following conditions, which would be incorporated into determining the fair value of the award at the date of grant? a. A stock option that vests upon attaining a specified earnings per share target. b. A stock option that vests if the employee provides five years of service to the entity. c. A stock option that vests if the entity experiences a "change of control event" as defined in the agreement. d. A stock option that can be exercised when the entity's stock price exceeds a specified amount