A broker offers to register all sellers who list their properties with the broker by a certain date in a sweepstakes. First prize is $1,000 to be donated by the charity of the winners choosing. Such a program is prohibited because the:

a. charity to receive the donation is not chosen by the licensee b. offer involves the promotion of the sale of real estate through a lottery or drawing c. amount to be donated is greater than $25 d. sellers who list with the broker after the specified period of time are discriminated against