The best question that could be formulated given the information on the statement, and which would lead to scientific research would be: Which of the four types of macromolecules, and in which proportions, are present in this food sample?
Explanation:
Literally, the statement wants to know who was responsible for the situation that arose through bringing food into the lab by determining the types of macronutrients that form that food. What the instruction then becomes is to determine the macromolecules (lipids, nucleic acids, proteins and carbohydrates) that are present in the food, given that while one type of food may have only one type of macromolecule, most will have a combination of them. It is also interesting to know the proportions of these macromolecules present in the food. These questions would lead to a good process of research, and if more people brought food, you could tell who brought the sample in question by learning the types of foods that were brought in.