1. Identify what is being asked

We need to determine which properties are shown by $\ce{CN^-}$ ion towards metal species:

• (a) reducing
• (b) oxidising
• (c) complexing

So we must check whether cyanide ion can act as:

1. a reducing agent,
2. an oxidising agent,
3. a complexing ligand.

2. Check complexing property

$\ce{CN^-}$ is a very well-known strong field ligand and forms very stable coordination compounds with many metals, for example:

• $\ce{[Fe(CN)6]^{4-}}$
• $\ce{[Fe(CN)6]^{3-}}$
• $\ce{[Ag(CN)2]^-}$

Hence, $\ce{CN^-}$ definitely shows complexing property.

So, property (c) is present.

3. Check reducing property

A reducing agent donates electrons or causes reduction of another species.

Cyanide ion can behave as a reducing agent toward certain metal ions. A standard example is its reaction with $\ce{Au^{3+}}$ or other metal species where cyanide participates in processes that reduce the metal center while forming stable cyanide complexes. Thus, in qualitative inorganic chemistry, $\ce{CN^-}$ is considered to show reducing behavior toward some metal species.

So, property (a) is present.

4. Check oxidising property

For an ion to act as an oxidising agent, it should itself get reduced.

In $\ce{CN^-}$, carbon is already in a low oxidation state and the ion is not generally known to oxidise metal species. Its chemistry with metals is dominated by:

• ligand/complex formation,
• and in some cases reducing behavior, not oxidising behavior.

So, property (b) is absent.

5. Conclusion

Thus, the set of properties shown by $\ce{CN^-}$ towards metal species is:

$\boxed{(c), (a)}$

This corresponds to Option A.

6. Compare with stored correct answer

Stored correct answer: A

Our derived answer: A

So, the derived answer agrees with the stored correct answer.