Choose what?

[Lyf]

Gary, Indiana, is a ----------- center of the United States
(A) leader in steel production
(B) production leader of steel
(C) leading steel production
(D) steel production leading

The right answer for this sentence is C, but I wonder why it is not B?

[Casiopea]

Originally Posted by Lyf

Gary, Indiana is a *production leader of steel center of the United States.

'production' modifies 'leader'. It tells us what kind of leader, not that steel is produced. It's not directly connected to 'steel', and it needs to be. Gary, Indiana leads the US in the production of steel, which makes it a leading steel production center.

Gary, Indiana leads (verb) => leading (participle)
the production (noun) => production (adjective)
of steel (noun) => steel (adjective)