**Core Concept**
In forensic pathology, postmortem lividity, also known as livor mortis, is the discoloration of the skin due to the pooling of blood in the dependent parts of the body after death. The color of lividity can provide important clues about the circumstances surrounding a death, including the body temperature at the time of death.

**Why the Correct Answer is Right**
In hypothermic deaths, the body temperature is significantly lower than normal, which affects the hemoglobin in red blood cells. Hemoglobin is a protein that carries oxygen in the blood, and in cold temperatures, it changes its shape and releases oxygen more slowly, resulting in a bright red or reddish-purple color of the lividity. This is because the cold temperature slows down the breakdown of hemoglobin, allowing it to remain in its oxygenated state for longer.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pale or white lividity is more commonly associated with deaths due to carbon monoxide poisoning, not hypothermia.
**Option B:** This option is incorrect because greenish or bluish discoloration is typically seen in deaths due to putrefaction, not hypothermia.
**Option C:** This option is incorrect because purple lividity is more commonly associated with deaths due to asphyxia or cardiac arrest, not hypothermia.

**Clinical Pearl / High-Yield Fact**
In forensic pathology, the color of lividity can provide important clues about the body temperature at the time of death. Remember that bright red or reddish-purple lividity is often associated with hypothermic deaths, while pale or white lividity may indicate carbon monoxide poisoning.

**Correct Answer: B. Reddish-purple**