In the cyanide extraction process of silver, the oxidizing and reducing agents used are:

\(O_2\) and \(Zn\) dust respectively

The correct answer is option 2. \(O_2\) and \(Zn\) dust respectively.

In the cyanide extraction process of silver, the cyanide ion (\(CN^-\)) is used as a complexing agent to form a soluble complex, \(Ag(CN)_2^-\), with silver ions (\(Ag^+\)) present in the ore. The subsequent steps involve the reduction of silver cyanide complex to metallic silver. This reduction is typically achieved using a reducing agent.

Let's analyze the options:

1. \(O_2\) and \(CO\) respectively - Oxygen (\(O_2\)) is not commonly used as a reducing agent in cyanide extraction processes. Carbon monoxide (\(CO\)) can be used as a reducing agent in certain metallurgical processes, but it is not commonly used in the cyanide extraction of silver.

2. \(O_2\) and \(Zn\) dust respectively - Oxygen (\(O_2\)) is typically used as an oxidizing agent rather than a reducing agent in cyanide extraction processes. Zinc (\(Zn\)) dust is commonly used as a reducing agent to reduce the silver cyanide complex to metallic silver. This option seems plausible.

3. \(H_2O\) and \(Zn\) dust respectively - Water (\(H_2O\)) is not typically used as an oxidizing or reducing agent in cyanide extraction processes. Zinc (\(Zn\)) dust is commonly used as a reducing agent, as mentioned earlier.

4. \(H_2O\) and \(NaCN\) respectively - Water (\(H_2O\)) is not an oxidizing or reducing agent in cyanide extraction processes. Sodium cyanide (\(NaCN\)) is the source of cyanide ions used as a complexing agent, but it is not used as a reducing agent.

Based on this analysis, option 2, \(O_2\) and \(Zn\) dust respectively, seems to be the most appropriate choice. Therefore, the correct answer is option 2.