Consider the following processes:
`O_(2)` evolution
2. `CO_(2)` fixation
3. NADPH formation
4. HMP pathway
Which of these do not occur in thylakoids?

Options

A. 1, 2 and 4
B. 2,3 and 4
C. 3 and 4
D. 2 and 4

Answer

To determine which processes do not occur in the thylakoids, we need to analyze each of the mentioned processes in relation to their location within the plant cell.

### Step-by-Step Solution:

1. **Understanding Thylakoids**:
- Thylakoids are membrane-bound structures found within chloroplasts, specifically in the grana. They are primarily involved in the light-dependent reactions of photosynthesis.

2. **Oxygen Evolution**:
- This process occurs during the light reactions of photosynthesis, specifically through the splitting of water (photolysis) in the thylakoids. Therefore, oxygen evolution **does occur** in the thylakoids.

3. **CO₂ Fixation**:
- CO₂ fixation is part of the Calvin cycle, which is a light-independent reaction (often referred to as the dark reaction). This process occurs in the stroma of the chloroplasts, not in the thylakoids. Hence, CO₂ fixation **does not occur** in the thylakoids.

4. **NADPH Formation**:
- NADPH is produced during the light reactions, specifically through non-cyclic photophosphorylation in the thylakoids. Thus, NADPH formation **does occur** in the thylakoids.

5. **HMP Pathway**:
- The HMP (Hexose Monophosphate) pathway is a metabolic pathway that occurs in the cytoplasm and is not directly related to the photosynthetic processes occurring in the thylakoids. Therefore, the HMP pathway **does not occur** in the thylakoids.

### Conclusion:
Based on the analysis:
- The processes that do not occur in the thylakoids are **CO₂ fixation (2)** and **HMP pathway (4)**.

Thus, the correct answer is **option 2 and 4**.