Task: Question Answering
Input (English): During a walk through the Arkansas River Valley, Alex found a rock that she determined was a sedimentary rock. Which characteristics of the rock would lead Alex to this conclusion?  
 (A) thin flaky sheets and very hard (B) glassy texture and a shiny black color (C) very rough texture with obvious crystals (D) sand-sized particles and a light brown color
Output (English): D