**Core Concept**
Phytobezoars are a type of bezoar, which is a concretion or mass of food that accumulates in the gastrointestinal tract. In the case of phytobezoars, they are composed of plant material that has become trapped and accumulated in the stomach or small intestine.

**Why the Correct Answer is Right**
Phytobezoars are typically formed from undigested fragments of plant material, such as seeds, pits, or other fibrous plant matter, that have not been properly broken down by digestive enzymes. These fragments can accumulate in the stomach or small intestine and form a concretion, which can cause obstruction or other complications. The formation of phytobezoars is often associated with eating certain types of foods, such as corn on the cob, celery, or other fibrous vegetables, without properly chewing them.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not specified, so it cannot be evaluated.
**Option B:** This option is not specified, so it cannot be evaluated.
**Option C:** This option is not specified, so it cannot be evaluated.

**Clinical Pearl / High-Yield Fact**
It is essential to note that phytobezoars can cause symptoms such as abdominal pain, nausea, vomiting, and constipation. If left untreated, they can lead to more severe complications, including intestinal obstruction or perforation.

**Correct Answer:** C. Plant material.