Which of the following proteins is found in plasma?

Plasma's function is to transport nutrients, hormones, and proteins throughout the body.
It also transports waste products of cell metabolism from different tissues to the organs that detoxify and/or excrete them.
Plasma is 90% water, with the remaining 10% consisting of ions, proteins, dissolved gases, nutritional molecules, and wastes.
Plasma proteins are of three different types: albumin, globulins, and fibrinogen.
Albumin:
- Albumin aids in the maintenance of the blood's colloid osmotic pressure.
- It is the smallest of the plasma proteins, but it accounts for the majority of the total.
- The blood's colloid osmotic pressure is critical for maintaining a balance between the water inside the blood and the water in the tissue fluid surrounding the cells.
- When plasma proteins are lacking, the water in the plasma leaks into the area around the blood vessels, causing interstitial edema, which is a symptom of liver illness, kidney disease, and malnutrition, among other things.
- Albumin also aids in the transfer of a variety of molecules, including medicines, hormones, and fatty acids.

Leptin:
- Leptin is a hormone released by adipose tissue (body fat) that helps your body maintain a healthy weight over time.
- This is accomplished by providing the sensation of satiety, which regulates appetite (feeling full).
- Insulin stimulates leptin secretion via a posttranscriptional process including the PI3K-PKBmTOR pathway, as well as other unidentified mechanisms.
Keratin:
- It is a protein that can be found in your hair, skin, and nails.
- Keratin is also found in the organs and glands of the body.
- Keratin protects epithelial cells, strengthens the skin, strengthens internal organs, controls the growth of epithelial cells, and maintains elasticity in the skin. It also holds epithelial cells together and helps them combat mechanical stress.
Insulin:
- Insulin is a hormone created by your pancreas that controls the amount of glucose in your bloodstream at any given moment.
- It also helps store glucose in your liver, fat, and muscles.
- It regulates your body's metabolism of carbohydrates, fats, and proteins.