Final answer:
The approximate temperature of the water is likely around 70°C, as it is hot enough to dissolve sugar effectively without reaching the boiling point of water, making Option C the most reasonable choice.
Step-by-step explanation:
The approximate temperature of the water used in the Sugar Measure Solubility in Hot Water lab is not explicitly stated in the given details. However, based on the context of dissolution and temperature changes in various scenarios provided, one could suggest a temperature that dissolves sugar effectively without reaching boiling point. Considering options B) 50°C and C) 70°C are within this range while allowing increased solubility compared to the normal room temperature, a temperature like 70°C would be reasonably hot to dissolve sugar quicker than at lower temperatures. Option D) 100°C, which is the boiling point of water, is likely too high for a lab setting focused on solubility unless specified for operations under boiling conditions. Therefore, the approximate temperature of the water used is likely around 70°C (Option C).