Answer:
The correct answer is : D The son's children, because their interest will vest, if at all, within a life in being plus 21 years.
Explanation:
In the case of a will, the perpetuities period begins to run on the date of the testator's death, and measuring lives used to show the validity of interest must be in existence at that time. This interest will vest, if it does vest, within 21 years after the friend's life, and is therefore not in violation of the Rule Against Perpetuities.