The process which do use catalysts are

Options

A. Contact process
B. Thermite process
C. Ostwald's process
D. Haber's process

Explanation

To determine which processes use catalysts, let's analyze each option provided in the question.

### Step-by-Step Solution:

1. **Contact Process**:
- The Contact Process is used to manufacture sulfuric acid (H2SO4).
- The overall reaction involves the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3) in the presence of a catalyst.
- The catalyst used in this process is vanadium pentoxide (V2O5).
- **Conclusion**: This process uses a catalyst.

2. **Thermite Process**:
- The Thermite Process involves the reduction of metal oxides using aluminum powder.
- The reaction typically involves iron(III) oxide (Fe2O3) being reduced to iron (Fe) by aluminum (Al) at high temperatures.
- This process does not involve a catalyst; it is a direct reaction between the reactants.
- **Conclusion**: This process does not use a catalyst.

3. **Ostwald Process**:
- The Ostwald Process is used to produce nitric acid (HNO3).
- The process involves the oxidation of ammonia (NH3) in the presence of a catalyst, typically platinum.
- The reactions include ammonia reacting with oxygen to form nitrogen monoxide (NO), which further reacts to form nitric acid.
- **Conclusion**: This process uses a catalyst.

4. **Haber Process**:
- The Haber Process is used to synthesize ammonia (NH3) from nitrogen (N2) and hydrogen (H2).
- The reaction occurs at high temperature and pressure, and it utilizes a catalyst, usually iron oxide with molybdenum.
- **Conclusion**: This process uses a catalyst.

### Final Answer:
The processes that use catalysts are:
- Contact Process (with V2O5)
- Ostwald Process (with platinum)
- Haber Process (with iron oxide and molybdenum)

### Summary of Correct Options:
- **Correct Options**: Contact Process, Ostwald Process, Haber Process
- **Incorrect Option**: Thermite Process