Task: Question Answering
Input (English): A hammer and a screwdriver are next to each other in the sunlight. After one hour, the hammer is hotter than the screwdriver. The shape and mass of each object may affect the amount of heat each object gains. Another explanation for the difference in temperature may be that the hammer and screwdriver are  
 (A) moving at different rates. (B) made of different materials. (C) used for different purposes. (D) picked up in different ways.
Output (English): B