**Core Concept**
The patient's presentation of hematuria, urinary retention, and a palpable bladder suggests a urethral obstruction, which is a medical emergency. The likely cause is a urethral injury or a urethral stricture, which can be due to a variety of factors including trauma, instrumentation, or iatrogenic causes.

**Why the Correct Answer is Right**
The patient's symptoms are consistent with a urethral injury, specifically a posterior urethral injury, which can occur due to a fall onto the perineum or a direct blow to the perineum. This type of injury can cause bleeding from the urethral meatus, urinary retention, and a palpable bladder due to the obstruction of the urethral lumen. The presence of blood at the external urethral meatus is a classic sign of a urethral injury.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not address the patient's symptoms of urinary retention and hematuria.
**Option B:** This option is incorrect as it is a condition that typically presents with flank pain and hematuria, but not urinary retention.
**Option C:** This option is incorrect as it is a condition that typically presents with abdominal pain, fever, and dysuria, but not urinary retention.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that any patient with signs of urethral injury, such as hematuria, urinary retention, and a palpable bladder, should undergo a retrograde urethrogram (RUG) to confirm the diagnosis and guide management.

**Correct Answer:** C. Posterior urethral injury.