 
<prompt> context: Robin tapped them on the shoulder after they had continued talking throughout the lecture for five minutes. 
 Question: Why did Robin do this? 
A. continue his lecture in silence B. tell them that they need to stop their conversation C. tell them that they needed to leave the hall 
Refer to the context provided to answer the question that follows: <response>: B. tell them that they need to stop their conversation 