Many times we do not listen intently to the other person. Instead we are usually doing what? Figuring out our next response.
Thinking about our next meal.
Looking for ways to get out of the conversation.
Planning on where we will be going after we leave our current location.

B

Figuring out our next response.

Thinking about our next meal.

Looking for ways to get out of the conversation.

i have real life evidence of this happening

the avg human is most likely to do the second option

This is really an opinion based question, as it very much depends on the type of person. Try to figure out what the kind of person your teacher or whoever assigned this question is.

If they are quiet and don't like to talk much, chances are they will be looking for ways to get out of the conversation. If they talk a lot and like talking, then they definitely won't try to get out.

If they are busy or always have somewhere to go, they will be planning on where to go.

If they are at a place to eat, or something they will be thinking about the next meal. This is the least likely, so if you have to randomly guess don't do this one.

If the person cares about the people they usually talk to, then chances are they will be trying to figure out their next response. I believe this is the most likely.

answer; form new memories;

answer; graduated cylinder;