This excerpt taken from the WFR DEF 14A filed Mar 16, 2007.
Nonqualified Stock Options
Under the plan, the Compensation Committee may grant nonqualified stock options pursuant to an award agreement. Each option represents the right to purchase one share MEMC common stock at a price per share established by the Compensation Committee on the date of grant.
Options must be exercised before expiration or termination, which is generally ten years after the date of grant or earlier as a result of death, disability or other termination of director service, employment or consulting service with MEMC. Payment of the exercise price may be made in full in cash or in shares of MEMC common stock valued at fair market value on the exercise date or a combination thereof. The Compensation Committee may also permit other methods of payment, including cashless exercise involving a broker or dealer approved by the Compensation Committee.