Task: Question Answering
Input (English): Some localized layers of rock contain the element iridium. Iridium is most often found in space objects such as meteoroids and asteroids. The discovery of these iridium-containing layers has been matched to which phenomena in Earth's history?  
 (A) tectonic plate separations (B) mass species extinctions (C) orbital path changes (D) magnetic pole reversals
Output (English): B