Eva's boyfriend says he loves her, but she wants proof. in order to obtain the most trustworthy nonverbal signals of how he really feels, eva should carefully observe:
a) his general body posture when he stands near her.
b) the way he holds her hand when they walk together.
c) how close he stands to her when they are talking.
d) his facial expressions when they spend time together.
e) the way he positions his legs when he sits near her.

D) His Facial expressions when they spend time together

 

Explanation:

Eva's should carefully observe the normal verbal signs by her lover because facial expression gives the hint to listener or viewer that one is interested towards other.

Some common facial Expression are

Smiling Eyes:While smiling is, of course, an important expression when we speak, attempting to keep a constant  smile could make you look more like a trained sociopath than a happy, enthusiastic presenter. These enables other person to feel the good vibes out of you and left a positive impact of your presence.Nod on: It is important to express interest in the feedback of your audience. No one likes an identity-centered snob. One way to show that you're actually engaged in the comments and questions they pose is by nodding while you're listening. Moving your head a little wider will help to express your attention as well.

                       

Answer body lying face up ;

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other