You are presented with the quiz "A what is used to keep food warm or to heat it up?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "apan is used for cooking food by heating food in it on a stove" and "an oven, stove, and microwave are available to keep food warm or to heat it up". 

So, what's the best answer to the question?


 

   pan        