**Core Concept**
Albumin, globulins, and fibrinogen are plasma proteins that vary in their electrophoretic mobility and lipid content, which is crucial for their function and clinical significance. Understanding the differences among these proteins is essential for diagnosing and managing various conditions, such as liver disease and multiple myeloma.

**Why the Correct Answer is Right**
Albumin has the highest electrophoretic mobility due to its small size, low charge density, and relatively low molecular weight. Additionally, albumin has the least lipid content among the options, which is approximately 0.5%. This characteristic allows albumin to bind and transport a wide variety of substances, including hormones, drugs, and ions, making it a crucial protein for maintaining osmotic balance and transporting essential nutrients.

**Why Each Wrong Option is Incorrect**
* **Option A:** Globulins have a higher molecular weight and charge density compared to albumin, resulting in lower electrophoretic mobility. Globulins also have a higher lipid content, typically around 2-5%.
* **Option B:** Fibrinogen is a large, glycoprotein with a high charge density, which leads to lower electrophoretic mobility. Fibrinogen also contains a significant amount of lipid, approximately 5-7%.
* **Option D:** Immunoglobulins are a type of globulin with a high molecular weight and charge density, resulting in lower electrophoretic mobility compared to albumin. Immunoglobulins also contain a higher percentage of lipid, typically around 5-7%.

**Clinical Pearl / High-Yield Fact**
Remember that albumin levels can be used as a marker for liver synthetic function, with decreased levels indicating liver dysfunction. Additionally, the albumin-to-globulin ratio can be used to diagnose and monitor conditions such as multiple myeloma and other plasma cell dyscrasias.

**Correct Answer:** A. Albumin has the highest electrophoretic mobility and least lipid content.