(A) ** Ruhr
(B) Saarland
(C) Alsace Lorraine
(D) Rhineland
EXPLANATIONS BELOW
Concept note-1: -Rhine-Ruhr also is one of the world’s 10 largest economic regions. Rhine-Ruhr, at the center of Germany’s industrial heartland, is the historic headquarters of steel, mining and automobile production.
Concept note-2: -The Ruhr valley is a major industrial and mining region; it includes the industrial cities of Essen, Düsseldorf, and Dortmund. The Ruhr coalfield is one of the world’s largest, and, although production had been curtailed sharply by the 21st century, it holds the bulk of Germany’s proven bituminous coal reserves.
Concept note-3: -Ruhr region is the most important industrial region of Germany.
Concept note-4: -Rhine-Ruhr is also one of the world’s ten most populous economic areas. Complete answer: The historic headquarters of steel, mining, and car manufacturing are located in Rhine-Ruhr, which is located in the heart of Germany’s industrial heartland.
Concept note-5: -The Ruhr Valley is important to Germany’s economy for its quality farmland and its natural resources of coal and iron.