I can't advise you what to do, you must use your own ().

A．usually used by children to get sweets from others
B．a warning used by criminals to snatch something
C．a secret was used by protestant gunmen to kill somebody
D．an old saying, but not used now

A．She was a protestant.
B．She enjoyed the "trick or treat" greeting.
C．She was only a girl of 19 years old.
D．We know nothing about her.