Silver halides are used in photography because they are

Options

A. Photosensitive
B. Soluble in hyposolution
C. Soluble in `NH_4OH`
D. Insoluble in acids

Explanation

To answer the question "Silver halides are used in photography because they are:", we will analyze each option and determine the correct answer based on the properties of silver halides.

### Step-by-Step Solution:

1. **Understanding Silver Halides**:
- Silver halides include compounds like AgCl (silver chloride), AgBr (silver bromide), and AgI (silver iodide). These compounds are known for their unique properties, particularly their behavior when exposed to light.

2. **Analyzing Photosensitivity**:
- Silver halides are known to be photosensitive, meaning they undergo a chemical change when exposed to light. This is crucial in photography, as the exposure to light allows for the formation of an image.
- When silver halides are exposed to light, they decompose into elemental silver and halogen gas (e.g., AgBr → Ag + 1/2 Br2). The elemental silver appears dark or black, which is essential for developing photographs.

3. **Evaluating Other Options**:
- **Option B: Soluble in hyposolution**: While silver halides can be dissolved in certain solutions (like sodium thiosulfate, known as hypo), this property is not the primary reason they are used in photography.
- **Option C: Soluble in NH4OH**: This is not a characteristic property of silver halides. They are not significantly soluble in ammonium hydroxide.
- **Option D: Insoluble in acids**: While silver halides are generally insoluble in acids, this property does not relate directly to their use in photography.

4. **Conclusion**:
- The primary reason silver halides are used in photography is their **photosensitivity**. This property allows them to react to light and form images, making option A the correct answer.

### Final Answer:
Silver halides are used in photography because they are **photosensitive**.