**Core Concept**
The most common cause of infection due to catheterization in the urinary tract is related to the colonization of the catheter's surface by microorganisms. This occurs due to the disruption of the normal urinary tract flora and the introduction of a foreign object that provides a conduit for bacterial growth.

**Why the Correct Answer is Right**
The correct answer is **Coagulase-Negative Staphylococci**. These bacteria are commonly found on the skin and can easily colonize the catheter's surface. They thrive in the moist environment of the urinary catheter and can cause a range of infections, from asymptomatic bacteriuria to more severe diseases such as urinary tract infections and sepsis. The biofilm formed by these bacteria on the catheter's surface makes them resistant to antibiotics and host immune defenses.

**Why Each Wrong Option is Incorrect**
* **Option A:** Gram-Negative Rods, such as Pseudomonas aeruginosa, are also a common cause of catheter-associated urinary tract infections, but they are not the most common cause.
* **Option B:** Escherichia coli is a common cause of urinary tract infections, but it is more commonly associated with spontaneous urinary tract infections rather than those caused by catheterization.
* **Option D:** Candida species can also cause urinary tract infections, especially in immunocompromised patients, but they are not the most common cause of catheter-associated infections.

**Clinical Pearl / High-Yield Fact**
Catheter-associated urinary tract infections are a significant concern in hospitalized patients, particularly those with indwelling catheters for extended periods. It is essential to implement appropriate infection control measures, such as proper catheter insertion and maintenance techniques, to minimize the risk of these infections.

**Correct Answer:** C.