**Core Concept**
The male urethra is a tube that carries urine from the bladder to the outside of the body, playing a crucial role in the urinary system. It is divided into three main parts: the prostatic, membranous, and penile urethra.

**Why the Correct Answer is Right**
The correct answer is the shortest part of the male urethra, which is the **membranous urethra**. This part is approximately 1-2 cm long and is located behind the pubic bone, passing through the urogenital diaphragm. It is surrounded by the external urethral sphincter muscle, which is responsible for controlling the flow of urine.

**Why Each Wrong Option is Incorrect**
**Option A:** The prostatic urethra is the longest part of the male urethra, approximately 3-4 cm long, and is located within the prostate gland.

**Option B:** The penile urethra is the longest part of the male urethra, approximately 15-20 cm long, and is located within the penis.

**Option D:** This option is incomplete, but we can assume it's an incorrect option.

**Clinical Pearl / High-Yield Fact**
The male urethra is surrounded by several important structures, including the external urethral sphincter muscle, the urogenital diaphragm, and the prostate gland. Understanding the anatomy of the male urethra is crucial for diagnosing and treating urinary tract disorders.

**Correct Answer: C. Penile urethra**