In the extraction of iron, carbon monoxide acts as O A catalyst OB an inert gas . an oxidising agent . a reducing agent .

a reducing agent .

Explanation:

In the extraction of iron, carbon monoxide acts as the main reducing agent.

Carbon monoxide is a neutral, colorless and odorless gas. One of the property of carbon monoxide is that it is a powerful reducing agent as it combines with oxygen readily to form CO₂ and hence its use in metallurgy.

A reducing agent is one that undergoes oxidation in a chemical process. The carbon monoxide is produced in the furnace at high temperature. Carbon dioxide combines with carbon to produce carbon monoxide.

So, carbon monoxide acts as the main reducing agent.

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later