Contraction of gall bladder is induced by

Options

A. gastrin
B. secretin
C. Cholecystokinin
D. enterogasterone

Explanation

To solve the question regarding which hormone induces the contraction of the gallbladder, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Function of the Gallbladder**: The gallbladder stores bile produced by the liver and releases it into the small intestine to aid in digestion, particularly in the emulsification of fats.

2. **Identify Relevant Hormones**: We need to analyze the hormones listed in the options to determine which one is responsible for gallbladder contraction.

3. **Evaluate Each Option**:
- **Option 1: Gastrin**: This hormone is secreted by the pyloric part of the stomach and primarily stimulates gastric juice secretion and gastric motility. It does not induce gallbladder contraction. Therefore, this option is incorrect.

- **Option 2: Secretin**: Secretin is secreted by the duodenum and acts on the pancreas and liver. It primarily stimulates the release of bicarbonate from the pancreas and increases bile secretion, but it does not induce gallbladder contraction. Thus, this option is also incorrect.

- **Option 3: Cholecystokinin (CCK)**: This hormone is secreted by the small intestine (duodenum) and is specifically known to stimulate the contraction of the gallbladder, leading to the release of bile. It also stimulates the pancreas to secrete digestive enzymes. This option is correct.

- **Option 4: Enterogastron**: Also known as gastric inhibitory polypeptide, this hormone is secreted by the duodenum and inhibits gastric secretion. It does not play a role in gallbladder contraction, making this option incorrect.

4. **Conclusion**: The hormone that induces the contraction of the gallbladder is **Cholecystokinin (CCK)**.

### Final Answer:
The contraction of the gallbladder is induced by **Cholecystokinin (CCK)**.