**Core Concept**
The diagnosis of septic arthritis relies on the analysis of synovial fluid aspirated from the affected joint, which can provide crucial information about the presence of infection. **Septic arthritis** is characterized by the invasion of the joint space by infectious agents, leading to an inflammatory response. The **synovial fluid analysis** is a key diagnostic tool in this condition.

**Why the Correct Answer is Right**
Although the options are missing, typically, the correct answer would involve characteristics such as a high number of **white blood cells (WBCs)**, especially **neutrophils**, indicating an acute inflammatory response. The presence of **bacteria** on **Gram stain** or **culture** would also be diagnostic.

**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it suggested normal or decreased WBC counts.
**Option B:** Might be wrong if it indicated the absence of bacteria or a low WBC count.
**Option C:** Could be incorrect if it suggested findings not consistent with infection.
**Option D:** Would be incorrect if it did not align with the expected findings in septic arthritis.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that septic arthritis is a medical emergency requiring prompt diagnosis and treatment to prevent joint destruction. The presence of more than 50,000 WBCs per mm^3 in the synovial fluid is highly suggestive of septic arthritis.

**Correct Answer:** D. More than 50,000 cells per cubic millimeter with a predominance of neutrophils.