$$

A small percentage, roughly only $\_\_\_\_\_\_\_\_\_\_\_\_$ percent, of American parents $[$with household incomes of over $$100,000$ per year$]$ had disclosed to their children, or planned to disclose to their children how much they earned annually and$/$or what was the total value of their $($the parents$)$ networth.

Question $30$ options:

$12$

$17$

$15$

$21$