## **Core Concept**
Prostate-Specific Antigen (PSA) is a protein produced by the prostate gland. Elevated levels of PSA in the blood can indicate prostate cancer, prostatitis, or benign prostatic hyperplasia (BPH). The test is commonly used for screening and monitoring prostate health.

## **Why the Correct Answer is Right**
The correct answer involves understanding the conditions that lead to an elevation in PSA levels. Prostate cancer (option C) is a well-known cause of elevated PSA because cancer cells can cause the prostate gland to release more PSA into the bloodstream.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain conditions like prostatitis (inflammation of the prostate) can indeed raise PSA levels, without specifying the condition, it's hard to assess its correctness directly. However, it's known that prostatitis can elevate PSA.
- **Option B:** Benign prostatic hyperplasia (BPH) or enlarged prostate can cause a mild elevation in PSA levels but is generally less significant than the elevation seen with prostate cancer.
- **Option D:** This option is not specified, but generally, conditions not directly related to the prostate (like certain medications, recent ejaculation, or testing errors) might not significantly impact PSA levels or could lead to false elevations.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while PSA is a useful screening tool, an elevated PSA level does not definitively diagnose prostate cancer. Additional tests, such as biopsy, are required for a definitive diagnosis. Also, recall that certain medications (e.g., 5-alpha-reductase inhibitors) can affect PSA levels.

## **Correct Answer:** C. Prostate cancer.