Extensive :

Expensive
Compact
Concrete
Abstract E. Narrow

The correct answer is: C. Concrete

Extensive means covering a large area or number of things. Concrete means specific and not abstract.

Expensive means costing a lot of money. Compact means small and neat. Abstract means not based on reality or physical things. Narrow means limited in scope or range.

For example, an extensive search would cover a large number of websites. A concrete example is something that is specific and not abstract.