**Core Concept**
Storage proteins are a class of proteins that play a crucial role in maintaining the osmotic balance and storing nutrients within cells. They are particularly abundant in the liver, muscles, and adipose tissue. Storage proteins are responsible for binding and storing various substances, including lipids, glycogen, and other nutrients.

**Why the Correct Answer is Right**
Storage proteins, such as albumin, globulins, and fibrinogen, are primarily involved in maintaining the osmotic pressure and storing nutrients. However, some proteins are not classified as storage proteins due to their distinct functions. For example, enzymes, hormones, and antibodies have specific roles in catalysis, signaling, and immune response, respectively.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because albumin is a storage protein that maintains osmotic pressure and stores various substances.
**Option C:** Incorrect because fibrinogen is a storage protein involved in clotting and storing nutrients.

**Clinical Pearl / High-Yield Fact**
It's essential to distinguish between storage proteins and other types of proteins, such as enzymes and hormones, which have distinct functions and are not involved in storing nutrients. This knowledge is critical in understanding various physiological and pathological processes.

**Correct Answer: D.**