**Core Concept**
Necrosis of the skin and variable thickness of the underlying subcutaneous tissue is a form of tissue damage characterized by cell death due to injury or infection. This condition is often classified based on the depth of involvement and can be caused by various factors such as trauma, burns, or infections.

**Why the Correct Answer is Right**
The correct answer describes a type of necrosis known as **full-thickness necrosis** or **full-thickness skin necrosis**, which involves the entire thickness of the skin, including the epidermis, dermis, and variable thickness of the underlying subcutaneous tissue. This type of necrosis can occur due to severe burns, trauma, or infections that compromise the blood supply to the affected area, leading to cell death. The extent of subcutaneous tissue involvement can vary depending on the severity of the injury or infection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might refer to partial-thickness necrosis, which would involve only the epidermis or the papillary dermis, but not the entire thickness of the skin.
**Option B:** This option might be a distractor related to another type of tissue damage, such as ischemic necrosis, but it does not accurately describe the condition described in the question.
**Option C:** This option could be a distractor related to a different type of skin lesion or condition, such as a skin abscess or cellulitis, but it does not accurately describe the condition described in the question.

**Clinical Pearl / High-Yield Fact**
It is essential to differentiate between partial-thickness and full-thickness necrosis, as the latter often requires more aggressive treatment and has a higher risk of complications, such as infection and scarring.

**Correct Answer:** B. Full-thickness necrosis