Which Is a Rule from the Wall Street Journal Article

Which is a rule from the Wall Street Journal article "The New Rules of Flirting"?

A) Do not flirt within a relationship that you want to strengthen.
B) Flirt with someone you know is looking for a relationship if you are not interested in a new relationship.
C) Flirt to make your partner jealous.
D) Flirting between power differences, such as boss and employee, is usually fine.
E) Do not make physical contact with the person you are flirting with, unless it is within a desired relationship.