**Core Concept**
Intraabdominal sepsis caused by a gram-positive, vancomycin-resistant, gentamycin-resistant, and ampicillin-resistant organism that grows well in the presence of 6.5% NaCl and arginine, and exhibits bile esculin hydrolysis, suggests the presence of an organism that is capable of tolerating high salt concentrations and has specific metabolic characteristics.

**Why the Correct Answer is Right**
The organism is likely **Enterococcus faecalis**, a gram-positive coccus that exhibits vancomycin resistance, gentamycin resistance, and ampicillin resistance. The organism grows well in the presence of 6.5% NaCl, which is indicative of its tolerance to high salt concentrations. Additionally, its ability to hydrolyze bile esculin is a key identifying characteristic, as it suggests the presence of the enzyme alpha-glucosidase. The organism's growth in the presence of arginine also supports this identification, as Enterococcus species are known to utilize arginine as a nutrient source.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option may represent a different gram-negative organism that does not match the described characteristics.
* **Option B:** This option may represent a different gram-positive organism that lacks the specific metabolic characteristics described.
* **Option C:** This option may represent a different organism that does not exhibit bile esculin hydrolysis or grow well in the presence of 6.5% NaCl.
* **Option D:** This option may represent a different organism that lacks the described vancomycin resistance and gentamycin resistance.

**Clinical Pearl / High-Yield Fact**
Enterococcus species are notorious for their ability to develop resistance to multiple antibiotics, making them challenging to treat. In this case, the organism's vancomycin resistance highlights the importance of using combination therapy and monitoring for antibiotic resistance patterns.

**Correct Answer:** C. Enterococcus faecalis