Task: Question Answering
Input (English): A student adds water and detergent to a cup of soil. The mixture is shaken and allowed to settle. The student observes that silt particles stay suspended long after the other particles form layers at the bottom of the jar. The most likely explanation is that the silt particles are  
 (A) organic. (B) dissolving. (C) less dense. (D) moving faster.
Output (English): C