Final answer:
Stock conversion plans are not one of the commonly used stock compensation plans, unlike stock option plans, Employee Stock-Purchase plans, and Restricted-stock plans.
Step-by-step explanation:
The commonly used stock compensation plans include stock option plans, Employee Stock-Purchase plans, and Restricted-stock plans. The option that is not one of these commonly used plans is a) Stock conversion plans. Stock option plans give employees the option to buy company stock at a predetermined price, Employee Stock-Purchase plans typically allow employees to purchase company stock at a discount, and Restricted-stock plans involve the distribution of company shares to employees with restrictions on when they can be sold.