In which combinations all the ligands are ambient in nature?

Options

A. `NO_(2),overline(S)CN` and `overline(C)N`
B. EDTA, `overline(S)CN`
C.
D. All of these

Explanation

To determine in which combinations all the ligands are ambient in nature, we need to understand the definition of ambient ligands. Ambient ligands are those ligands or molecules that contain more than one donor species or lone pair donating species, but at a time only one atom can donate the lone pair of electrons.

### Step-by-Step Solution:

1. **Define Ambient Ligands**:
Ambient ligands are ligands that have multiple donor atoms but can only donate one lone pair at a time.

2. **Analyze the Options**:
We will examine each option provided to see if all ligands in that option qualify as ambient ligands.

3. **Option A: Nitro Group (NO2) and SCN**:
- The nitro group can donate from either nitrogen or oxygen, but only one can donate at a time. Thus, it is ambient.
- The thiocyanate (SCN) can also donate from either sulfur or nitrogen, making it ambient as well.
- Therefore, both ligands in option A are ambient.

4. **Option B: EDTA and SCN**:
- EDTA has multiple donor atoms (6 in total: 2 nitrogen and 4 oxygen). Since it can donate multiple lone pairs at once, it is not ambient.
- SCN is ambient, but since EDTA is not, this option does not qualify.

5. **Option C: H2O and Pyridine**:
- H2O has only one donor (oxygen), making it not ambient.
- Pyridine has a nitrogen donor, which is also not ambient since it does not have multiple donor species.
- Therefore, this option does not qualify.

6. **Option D**:
- Without specific ligands mentioned, we assume it does not qualify as ambient.

7. **Conclusion**:
After analyzing all options, we find that only option A contains ligands that are all ambient in nature.

### Final Answer:
The right answer for the given question is **Option A**.