Task: Question Answering
Input (English): A student concludes that a chemical reaction performed in a classroom investigation was exothermic. To communicate the validity of this conclusion, which would make the best visual evidence in a presentation?  
 (A) photographs of reactants and products (B) listing of masses of reactants and products (C) listing of time from start to finish of reaction (D) photograph of a flame produced when the chemicals reacted
Output (English): D