What did Germany do in March of 1938 and how did Britain and France react?

On 7 March 1936 German troops marched into the Rhineland. This action was directly against the Treaty of Versailles which had laid out the terms which the defeated Germany had accepted. This move, in terms of foreign relations, threw the European allies, especially France and Britain, into confusion.

Explanation:

the graph shows the spread of railways in the 1800s.

based on the graph, the conclusion that can be drawn about germany is answer d)   by 1880, germany had more rail lines than great britain and russia.