Subject to Section 4 hereof, one-third of the Option shall vest and become exercisable as of the first anniversary of the Date of Option Grant (“ Grant Date ”) and an additional one-third of the Option shall vest and become exercisable on each of the second and third anniversaries of the Grant Date. For purposes of this Agreement, the term “ Vested Portion ” of the Option means that portion which: (i) shall have become exercisable pursuant to the terms of this Agreement; (ii) shall not have been previously exercised; and (iii) shall not have expired, been forfeited or otherwise canceled in accordance with the terms hereof or the Plan. For purposes of this Agreement, the term “ Non-Vested Portion ” of the Option means that portion of the Option that is not vested or exercisable and which has not otherwise expired, been forfeited or canceled in accordance with the terms hereof or the Plan.