Which of the following BEST explains why the natural family planning method should be used by long-term couples only?
A.
This method is the least effective method of all birth controls.
B.
This method requires the couple to be prepared for a child.
C.
This method protects against numerous STIs.
D.
This method is 100% effective if done correctly.

Please select the best answer from the choices provided.

A
B
C
D