Ay$-$Bee$-$Cee$-$Dee Corp. has filed a Subchapter S election under the Internal Revenue Code for taxation purposes. As you know, $S$ corporations are allowed only a limited number of shareholders and, regardless of the number, certain types of entities, including other corporations, cannot be shareholders in $S$ corporations. Carter wants to transfer his shares of Ay$-$Bee$-$Cee$-$Dee Corp. to CarCor, Inc., a corporation that he and his brothers own. If Able, Baker, and Dennis want to preserve their Subchapter $S$ election and, thus, block the transfer of Carter's shares to CarCor $($without being stuck having to purchase Carter's shares themselves$),$ which of the following transfer restrictions would best allow them to accomplish their goal?

Multiple Choice

Provision disqualifying purchasers

Right of first refusal

Option agreement

Consent restraint

Buy and sell agreement