Fishes are a rich source of various nutrients and substances that are beneficial for human health. They provide essential proteins, vitamins, and minerals that are necessary for the proper functioning of our body. In particular, fishes are a good source of proteins and vitamin D. Additionally, fishes also contain oil, which is another important product that can be obtained from them.

Here is a detailed explanation of each option:

1. Proteins and Vitamin D: Fishes are an excellent source of high-quality proteins. Proteins are essential for the growth and development of the body, as they are the building blocks of tissues, muscles, and organs. Fishes also contain vitamin D, which plays a crucial role in maintaining bone health and improving the absorption of calcium in the body.

2. Wool: Wool is obtained from sheep and other animals like goats and alpacas, but not from fishes. Fishes do not produce wool or any other fibrous material that can be used for textile purposes.

3. Oil: Fishes, especially fatty fishes like salmon, mackerel, and sardines, are a rich source of omega-3 fatty acids. These fatty acids are beneficial for heart health, reducing inflammation, and improving brain function. Fish oil, extracted from fish tissues, is commonly consumed as a dietary supplement due to its numerous health benefits.

Therefore, the correct answer is option 'D' - Both A and C. Fishes can provide proteins and vitamin D, as well as oil, making them a valuable source of essential nutrients for our body. It is important to include fishes in our diet to ensure a well-rounded intake of these beneficial substances.