If the Subject Matter of an Offer Becomes Illegal,what Is

If the subject matter of an offer becomes illegal,what is the result?

A) The offer immediately terminates.
B) There is no effect as long as the offer was made at least one day before the subject matter of the offer became illegal.
C) There is no effect as long as the offer was made at least ten days before the subject matter of the offer became illegal.
D) There is no effect as long as the offer was made at least fifteen days before the subject matter of the offer became illegal.
E) There is no effect as long as the offer was made at least thirty days before the subject matter of the offer became illegal.