**Core Concept**
In cases of complete hanging, the duration of suspension plays a crucial role in determining the pattern of hypostasis. The longer the duration, the more the blood settles due to gravity, resulting in a distinct pattern of hypostasis.

**Why the Correct Answer is Right**
When a person is suspended in complete hanging for more than 8 hours, the blood settles in the lower extremities due to gravity, resulting in hypostasis. This is because the force of gravity pulls the blood downwards, causing it to accumulate in the lower parts of the body. The brain and upper parts of the body, being above the point of suspension, have less blood accumulation. This pattern of hypostasis is a key forensic indicator of the duration of suspension.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because hypostasis in the upper extremities is more likely in cases of incomplete hanging or suspension for less than 8 hours.
**Option B:** Incorrect because hypostasis in the lower back is more characteristic of death due to other causes, such as cardiac arrest or stroke.
**Option C:** Incorrect because hypostasis in the upper back is not a reliable indicator of the duration of suspension.

**Clinical Pearl / High-Yield Fact**
In forensic medicine, the pattern of hypostasis can provide valuable clues about the duration and circumstances of death, particularly in cases of hanging.

**Correct Answer:** D. Lower extremities