Wrinkles Skin Wrinkles Are Caused by a Variety of Factors. Some

Wrinkles
Skin wrinkles are caused by a variety of factors. Some of these factors are intrinsic, meaning that you cannot control them because they occur naturally. Others are extrinsic, meaning that they are caused by circumstances outside of the body.
One intrinsic factor is aging. As you age, your skin loses collagen, which is the protein responsible for keeping your skin elastic. With less collagen, your skin becomes thinner and more fragile. Aging also reduces the functioning of sweat and oil glands, which work to keep the skin looking smooth. You also lose fat in the deeper layers of your skin as you age. This fat loss causes your skin to sag and develop deeper wrinkles.
The two most common extrinsic factors are exposure to ultraviolet radiation (UV rays) and smoking. UV rays in sunlight break down your skin's connective tissue and collagen fibers. To prevent the appearance of wrinkles (as well as protect yourself from skin cancer) , you should always use UV-blocking sunscreen. The nicotine in cigarettes is the most likely link between smoking and wrinkles. Nicotine narrows the blood vessels, reducing the blood supply to your skin tissue. This deprives your skin of oxygen and important nutrients, causing damage that contributes to wrinkles.
Question: What is the primary purpose of the passage?

A) To entertain the reader regarding stories about aging and the changing nature of the skin.
B) To describe both intrinsic and extrinsic factors associated with skin wrinkles.
C) To inform the reader of the intrinsic scientific processes related to aging.
D) To persuade readers to protect themselves against exposure to ultraviolet radiation and limit smoking in order to prevent wrinkles.