Task: Question Answering
Input (English): The elements carbon, hydrogen, and oxygen are parts of many different compounds. Which explains why these three elements can make so many different compounds?  
 (A) They can be solids, liquids, or gases. (B) They come in different sizes and shapes. (C) They combine in different numbers and ratios. (D) They can be a proton, a neutron, or an electron.
Output (English): C