Choices:
 (1). Even if they are rude towards you in the moment, remember that it is better to be safe than sorry. Listen to them out loud, and make eye contact.;
 (2). Let your coworker finish talking before making your response. After they are done talking, allow a respectful pause to follow before giving a polite " no.;
 (3). Instead, remind yourself that you are not obligated to say no. If you are giving a coworker a turn to order coffee, tell them that you are expected to do so.;
 (4). Ask yourself if your coworker is honest about their actions and interests. Ask yourself what you hope to achieve on this day.;Choose from options above and answer: What most naturally follows?

How to say no to a coworker 
Listen to your coworker. 
Even if you know that you are going to say when a coworker approaches you, it is respectful hear them out. Being rude only builds enemies.
Answer:
(2).