The correct order of electron affinity is :-

Options

A. `ClgtFgtO`
B. `FgtOgtCl`
C. `FgtClgtO`
D. `OgtFgtCl`

Answer

To determine the correct order of electron affinity among the elements mentioned, we will analyze the electron affinity trends in the periodic table.

### Step-by-Step Solution:

1. **Understanding Electron Affinity**:
- Electron affinity is the energy change that occurs when an electron is added to a neutral atom. A more negative electron affinity indicates a greater tendency to gain an electron.

2. **Comparing Chlorine and Fluorine**:
- Chlorine (Cl) has a higher electron affinity than Fluorine (F). Although fluorine is more electronegative, its small atomic size leads to increased electron-electron repulsion when an additional electron is added. This repulsion makes it less favorable for fluorine to gain an electron compared to chlorine.

3. **Comparing Fluorine and Oxygen**:
- Fluorine has a higher electron affinity than Oxygen (O). This is because, as we move across the period from left to right, the electron affinity generally increases. However, the small size of fluorine leads to repulsion when an electron is added, but it is still more favorable than adding an electron to oxygen.

4. **Final Order of Electron Affinity**:
- Based on the comparisons, we can conclude the order of electron affinity is:
- Chlorine (Cl) > Fluorine (F) > Oxygen (O)

### Conclusion:
Thus, the correct order of electron affinity is:
**Cl > F > O**