Task: Question Answering
Input (English): A student investigates the effect of temperature on the distance a caterpillar travels in one minute. The student performs the investigation at four different times of day using one caterpillar. This experiment could be improved if the student  
 (A) uses more than one caterpillar. (B) performs the investigation on a wet surface. (C) uses earthworms instead of caterpillars. (D) performs the investigation at the same time on four days.
Output (English): A