Correct Option (a):
Berlin, the capital of Germany, is situated on the River Spree. The River Rhine, in contrast, flows through western Germany, associated with cities such as Cologne and Düsseldorf.
Incorrect Options:
London is correctly matched with the River Thames, which flows through southern England.
New York City is correctly located on the Hudson River, which traverses New York State.
Vienna, the capital of Austria, is correctly situated on the Danube River, a major waterway in Central and Eastern Europe.