Rocky Mountain Spotted fever is caused by:

Options

A. Rickettsia
B. Rochalimaea
C. Spirochaetes
D. Chlamydia

Answer

**Step-by-Step Solution:**

1. **Identify the Question:** The question asks about the causative agent of Rocky Mountain Spotted Fever.

2. **Review the Options Provided:**
- Option 1: Rickettsia
- Option 2: Rheumatoid Arthritis
- Option 3: Spirochete
- Option 4: Chlamydia

3. **Evaluate Each Option:**
- **Option 1: Rickettsia** - This is the correct answer. Rocky Mountain Spotted Fever is caused by the bacterium *Rickettsia rickettsii*.
- **Option 2: Rheumatoid Arthritis** - This is incorrect. Rheumatoid Arthritis is an autoimmune disorder, not an infectious disease.
- **Option 3: Spirochete** - This is incorrect as well. While Spirochetes are a type of bacteria that can cause diseases like Lyme disease, they do not cause Rocky Mountain Spotted Fever.
- **Option 4: Chlamydia** - This is also incorrect. Chlamydia is a sexually transmitted infection and does not cause Rocky Mountain Spotted Fever.

4. **Conclusion:** The only correct option that causes Rocky Mountain Spotted Fever is **Rickettsia**.

**Final Answer:** Rocky Mountain Spotted Fever is caused by *Rickettsia rickettsii*.

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