Nine-Year-Old Melissa Insists on Having a Lock on Her Bedroom

Nine-year-old Melissa insists on having a lock on her bedroom door.She will not change her clothes in front of her parents or her siblings.It is probably best for her parents to respond to this by

A) gently asking her if someone is harassing or molesting her.
B) informing her that there is nothing to be ashamed of and parents have a right to enter her room.
C) affirming that everyone is entitled to privacy and recognizing that their daughter is pretty typical.
D) increasing the amount of adult nudity she sees so that she will know her body is normal.