Final answer:
Leaning back in your chair is not considered positive body language because it may suggest disinterest or a lack of engagement, in contrast to maintaining eye contact and a body positioning that indicates attentiveness.
Step-by-step explanation:
The student has asked which of the following is NOT an example of positive body language: a) Acknowledging with nods of the head, b) Holding your body in a relaxed position, c) Leaning back in your chair, d) Facing the other person. The correct answer to this question is c) Leaning back in your chair, as it can be perceived as disinterest or a lack of engagement in the conversation. Positive body language includes eye contact, appropriate body positioning, and being aware of facial expressions and gestures to create a good impression and to show that you are engaged in the conversation.