Ethical topics are often closely related to issues of law, etiquette, or religion.

Which of the following is an issue of law?

a$.)$ Landlord Hank installs working smoke detectors in all of his properties.

b$.)$ Gene wears a yarmulke or skullcap in public.

c$.)$ Marcus breaks up with his girlfriend via text message.

d$.)$ The Rivera family goes to church every Sunday.