**Core Concept**
Urinary tract tuberculosis (TB) is a form of extrapulmonary tuberculosis that affects the kidneys, ureters, bladder, or urethra. The diagnosis of urinary tract TB typically requires a combination of clinical findings, laboratory tests, and imaging studies. Imaging plays a crucial role in confirming the diagnosis and assessing the extent of the disease.

**Why the Correct Answer is Right**
The investigation of choice for imaging of urinary tract tuberculosis is intravenous urography (IVU), also known as an intravenous pyelogram (IVP). IVU involves the injection of a contrast agent that is excreted by the kidneys, allowing for detailed visualization of the urinary tract. This imaging modality is particularly useful in detecting filling defects, such as tuberculosis lesions, in the kidneys, ureters, and bladder. IVU is also useful in assessing the function of the kidneys and the patency of the ureters.

**Why Each Wrong Option is Incorrect**
**Option A:** Ultrasound is not the investigation of choice for urinary tract TB as it may not provide sufficient detail to detect small lesions or assess the function of the kidneys.

**Option B:** Computed tomography (CT) scan may be useful in detecting complications of urinary tract TB, such as hydronephrosis or perinephric abscess, but it is not the primary imaging modality for diagnosing urinary tract TB.

**Option C:** Magnetic resonance imaging (MRI) is not typically used for the initial evaluation of urinary tract TB due to its limited availability and higher cost.

**Clinical Pearl / High-Yield Fact**
In patients with suspected urinary tract TB, it is essential to consider the possibility of coexisting pulmonary TB, as both conditions often occur simultaneously.

**Correct Answer:** C.