You are presented with the quiz "Tungsten filaments sealed in a glass bulb are used for what in the dark?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "alight bulb is used for seeing in the dark" and "incandescent light bulbs use a tungsten filament sealed inside a glass bulb". 

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


 

   seeing        