**Core Concept**
Death in fresh water occurs due to the phenomenon of "hypoxic hypoxia" or "anoxic anoxia" caused by the rapid dilution of oxygen in the blood. This results in a decrease in oxygen levels, leading to tissue hypoxia and ultimately, cell death. The primary mechanism behind this process is the diffusion of gases in water, particularly the rapid exchange of oxygen and nitrogen.

**Why the Correct Answer is Right**
The correct answer is based on the principle that the solubility of gases in water is inversely proportional to the temperature. In fresh water, the diffusion of gases is rapid, leading to a rapid decrease in oxygen levels. This is because the partial pressure of oxygen in fresh water is lower than in air, causing a net diffusion of oxygen from the lungs into the water. The rate of diffusion is further increased by the high surface area of the lungs and the presence of surfactants in the alveoli. As a result, the oxygen levels in the blood decrease rapidly, leading to tissue hypoxia and cell death.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the time frame for death in fresh water. While it is true that death can occur in fresh water, the exact time frame depends on various factors, including the depth and temperature of the water.
**Option B:** This option is incorrect because it does not provide a specific time frame for death in fresh water. While it is true that death can occur in fresh water, the exact time frame depends on various factors, including the depth and temperature of the water.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the rate of diffusion of gases in water is inversely proportional to the temperature. This means that death in fresh water can occur even at shallow depths if the water is cold. For example, death can occur in as little as 5-10 minutes in cold water (less than 10°C).

**Correct Answer:** C.