Read the given passage and answer the questions.
In the following chemical reaction "zinc oxide reacts with carbon to produce zinc metal and carbon monoxide."
`ZnO +C to Zn + CO`
The reactions used in black and white photography:

Options

A. Decomposition of silver bromide
B. Decomposition of silver chloride
C. Both
D. None of the above

Explanation

To solve the question regarding the chemical reactions used in black and white photography, we will break down the information provided in the passage and analyze the relevant chemical reactions.

### Step-by-Step Solution:

1. **Identify the Chemical Reaction**:
The passage mentions a reaction where zinc oxide (ZnO) reacts with carbon (C) to produce zinc metal (Zn) and carbon monoxide (CO). The chemical equation for this reaction is:
\[ \text{ZnO} + \text{C} \rightarrow \text{Zn} + \text{CO} \]

2. **Understand the Context of Black and White Photography**:
The question then shifts focus to the reactions used in black and white photography. The key reactions in this context involve silver compounds, specifically silver chloride (AgCl) and silver bromide (AgBr).

3. **Identify the Relevant Reactions**:
- **Decomposition of Silver Chloride**:
\[ \text{2 AgCl} \xrightarrow{\text{sunlight}} \text{2 Ag} + \text{Cl}_2 \]
- **Decomposition of Silver Bromide**:
\[ \text{2 AgBr} \xrightarrow{\text{sunlight}} \text{2 Ag} + \text{Br}_2 \]

4. **Conclusion**:
The reactions that are primarily used in black and white photography are the decomposition reactions of silver chloride (AgCl) and silver bromide (AgBr) when exposed to sunlight. Therefore, both reactions are correct in the context of black and white photography.

5. **Final Answer**:
The correct answer is that both the decomposition of silver chloride (AgCl) and silver bromide (AgBr) are used in black and white photography.