**Core Concept**
The "string of beads" appearance on a horizontal abdominal view X-ray refers to a radiographic pattern seen in the small intestine, characterized by multiple, evenly spaced, rounded or oval opacities that resemble a string of beads. This appearance is due to the presence of air-filled intestinal loops that are separated by thickened intestinal walls.

**Why the Correct Answer is Right**
The "string of beads" appearance is typically seen in cases of intestinal obstruction, where the small intestine is distended and the intestinal walls are thickened due to edema and inflammation. The evenly spaced opacities represent the air-filled intestinal loops, while the thickened intestinal walls are not visible on the X-ray but are inferred from the spacing and appearance of the air-filled loops. This radiographic pattern is often seen in conditions such as small bowel obstruction, intussusception, or Crohn's disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not related to the "string of beads" appearance, which is a specific radiographic pattern seen in the small intestine.
**Option B:** This option may be related to a different radiographic pattern, such as the "target sign" seen in conditions like intussusception, but it is not the correct answer for the "string of beads" appearance.
**Option C:** This option is not a known radiographic pattern or condition that would produce the "string of beads" appearance.

**Clinical Pearl / High-Yield Fact**
The "string of beads" appearance is a classic radiographic sign of small bowel obstruction, and it is essential to recognize this pattern to diagnose and manage conditions like intussusception or Crohn's disease.

**Correct Answer:** C. Small bowel obstruction.