Which of the Following Conduct Would Be Likely to Invalidate

Which of the following conduct would be likely to invalidate a will?

A) Marta urges her husband to leave all of his property to her,and he does.
B) Shirley,who was not a blood relative,took care of Elsie during an extended recovery after surgery.While Elsie was in a weakened condition,Shirley urged Elsie to name her sole beneficiary to the exclusion of her children,which she did.
C) Paul does not mention his oldest child in his will.
D) Lester gets remarried,and the new wife has young children.