Final answer:
Water would absorb the most heat in order to reach 100 degrees Celsius.
Step-by-step explanation:
The substance that would absorb the most heat in order to reach 100 degrees Celsius would be water (option A).
Water has a high specific heat capacity, which means it requires a large amount of heat energy to raise its temperature. In comparison, the specific heat capacities of water vapor and aluminum are lower, meaning they require less heat energy to reach the same temperature.
To illustrate this, let's consider the experiment where 1 g samples of each substance are placed in a hot oven. Water would absorb more heat energy than the other substances, causing its temperature to rise to 100 degrees Celsius.