Task: Question Answering
Input (English): While conducting an investigation on refraction, a teacher uses a red laser pointer to show how a beam of light is affected as it passes through several glass objects. The teacher should make sure that the  
 (A) room is totally dark. (B) light source is ultraviolet. (C) beam of light does not travel toward the students. (D) room walls are shielded with insulating material.
Output (English): C