Answer:
The correct answer is option B. "Fill a clear cube with them".
Step-by-step explanation:
Sugar crystals, colloquially known as "rock candy", are conglomerates of sugar molecules that are formed when sugar-saturated water are cooled. Sugar crystals are arranged in a three dimensional repeating pattern, forming a cube like structure. Therefore, Juan could fill a clear cube with its plastic foam balls to represent sugar crystals. I attached an image of sugar crystals dissolving in water as reference.