**Core Concept:**
The question is testing the understanding of hormones that can influence intestinal motility, which is the coordinated contractions of the smooth muscles in the walls of the gastrointestinal tract. This is essential for the smooth transit of food through the gastrointestinal tract and maintaining bowel function.

**Why the Correct Answer is Right:**
The correct answer, "Gastrin", is a hormone involved in regulating stomach acid secretion and gastric motility. Gastrin is produced by the G cells in the stomach and released in response to food ingestion. It stimulates the secretion of gastric acid into the stomach, which is essential for food digestion. Interestingly, gastrin also has a direct effect on the smooth muscles of the stomach to increase its contractility. However, in this question, we are focusing on its effect on the intestines, where gastrin indirectly inhibits intestinal motility.

**Why Each Wrong Option is Incorrect:**
A. **Gastrin**: As mentioned before, gastrin increases gastric contractility, not intestinal motility, making it incorrect for this question.
B. **Glucagon**: Glucagon is another hormone produced by the alpha cells in the pancreas and is primarily involved in increasing blood glucose levels by stimulating hepatic gluconeogenesis and glycogenolysis. It does not have a direct effect on intestinal motility.
C. **Somatostatin**: Somatostatin is a hormone produced by the D cells of the pancreas and the enteroendocrine cells in the gastrointestinal tract. It acts as a brake on various hormonal and neuroendocrine functions, including the secretion of gastric acid and the release of digestive enzymes. However, it does not directly affect intestinal motility.
D. **Somatostatin**: Similar to somatostatin, secretin is a hormone produced by the E cells of the duodenum in response to acidic chyme. Secretin stimulates the pancreas to secrete digestive enzymes and bicarbonate ions into the duodenum, which helps to neutralize the acidic chyme and facilitate digestion. Secretin has no direct effect on intestinal motility.

**Clinical Pearl:**
Intestinal motility is primarily regulated by the autonomic nervous system, particularly the parasympathetic and sympathetic divisions. The parasympathetic division, via the vagus nerve, stimulates intestinal motility by increasing the frequency and amplitude of contractions, while the sympathetic division, via the sympathetic nervous system, inhibits intestinal motility.

**Why the Correct Answer is Right:**
The correct answer, **Dopamine**, is a neurotransmitter synthesized in the enteric neurons of the gastrointestinal tract and the central nervous system. Dopamine plays a crucial role in regulating intestinal motility, particularly the sympathetic division's inhibitory effect on intestinal motility. Dopamine acts on D2 receptors in the enteric neurons, leading to a decrease in intestinal motility.

**Why Each Wrong Option is Incorrect:**
A. **Noradrenaline**: Noradrenaline is a neurotransmitter synthesized in the sympathetic neurons of the autonomic nervous system. It is responsible for stimulating intestinal motility via the sympathetic division by acting on alpha and beta receptors.