I believe the answer is C. Single..
Hope this helps
Answer:
Sender: This is the person that is delivering a message to a recipient. ... Receiver: The receiver is the person who is getting or receiving the message. Feedback: In some instances, the receiver might have feedback or a response for the sender. This starts an interaction.
Explanation:
Make sure to paraphrase this.
Answer:
B.) Cross-country skiing; tennis
Hope this helps :)