(a) A corporation may accept a subscription by notifying the subscriber in writing.
(b) A subscription to purchase shares in a corporation in the process of being formed is irrevocable for six months if the subscription is in writing and signed by the subscriber, unless the subscription provides for a longer or shorter period or all of the other subscribers agree to the revocation of the subscription.
(c) A written subscription entered into after the corporation is formed is a contract between the subscriber and the corporation.