An autoimmune disease is

Options

A. Rheumatoid arthritis
B. Multiple sclerosis
C. Insulin dependent diabetes
D. All the above

Answer

To answer the question "An autoimmune disease is," we will analyze the options provided and understand what an autoimmune disease entails.

### Step-by-Step Solution:

1. **Define Autoimmune Disease**:
An autoimmune disease is a condition where the immune system mistakenly attacks the body's own cells, tissues, or organs, thinking they are foreign invaders.

2. **Examine the Options**:
- **Option 1: Rheumatoid Arthritis**: This is an autoimmune disorder characterized by inflammation of the joints, leading to pain and swelling. The immune system attacks the joint tissues.
- **Option 2: Multiple Sclerosis**: This is another autoimmune disease where the immune system attacks the protective covering of nerves in the central nervous system, affecting movement and coordination.
- **Option 3: Insulin-Dependent Diabetes (Type 1 Diabetes)**: In this condition, the immune system attacks and destroys the insulin-producing beta cells in the pancreas, leading to high blood sugar levels.
- **Option 4: All of the Above**: This option suggests that all the previous conditions are autoimmune diseases.

3. **Conclusion**:
Since all three options (rheumatoid arthritis, multiple sclerosis, and insulin-dependent diabetes) are indeed autoimmune diseases, the correct answer is **Option 4: All of the Above**.

### Final Answer:
An autoimmune disease is **Option 4: All of the Above**.

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