The correct answer is option 3, Wool. Wool is a natural polymer made of protein.

Option 1, Rubber, is not made of protein. Rubber is a synthetic polymer made from petroleum or plant-based sources.

Option 2, Cotton, is also not made of protein. Cotton is a plant-based fiber made of cellulose, another type of natural polymer.

Option 4, Jute, is another plant-based fiber, but it is not made of protein either. Jute is made from the outer stem of the jute plant and is composed of cellulose fibers.

It is important to note that proteins are large biological molecules made up of amino acids, and they have diverse functions in living organisms. Wool is a specialized protein fiber produced by animals such as sheep, goats, and alpacas. It is characterized by its softness, warmth, and ability to retain heat. Wool is commonly used in textile industries for making clothing, carpets, and other fuzzy textile products.