D
Below is a question with multiple-choice answers. Choose the correct option based on your reasoning.

### Question:
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?

### Choices:
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

### Answer:
