Final answer:
Option B, 'This is true except in the case of water,' is correct. While most substances decrease in density with increasing temperature, water is unique because it reaches maximum density at around 4°C and then becomes less dense as it turns into ice.
Step-by-step explanation:
The density of any substance decreases as the temperature increases under any condition. This is true with the exception of water. This pattern holds for most substances because as the temperature increases, so does the amplitude of thermal motions, which causes substances to expand and thus become less dense. However, water displays an unusual property; its density increases as it cools, reaching a maximum at about 4°C, after which it decreases again as water turns into ice. This is due to the hydrogen bonding in water, which creates an open hexagonal lattice in ice that takes up more space than liquid water.