In His Observations of Heterosexual Strangers in Bar Situations, Perper

In his observations of heterosexual strangers in bar situations, Perper found if people were mutually attracted to each other the first indication was what?

A) They turn their bodies more toward each other until they are facing each other.
B) Their facial expressions and posture starts to mirror each other.
C) One will casually lean against the other to create minimal body contact.
D) The man typically initiates physical contact by touching the arm of the female.