Definition: In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: What countries were part of the pact that saw prefabricated concrete structures modernized? Passage:Four days before the end of the Second World War, undefended Bergen was occupied by the Red Army on 4 May 1945. After the German Democratic Republic (East Germany) was founded, the new government pressed ahead with further industrialization. In 1952, construction began on the industrial area on the town's western outskirts. From 1953 to 1958, the dairy was established, which furnished 300 tonnes of milk daily. In 1955/1956 came the establishment of the VEB Brot- und Backwaren (Bread and Baked Goods). In 1957/1958, the slaughterhouse and meat plant went into production. An efficient food industry was set up in Bergen, supplied from the island and parts of the mainland. Since Reunification and East Germany's accession into the Federal Republic, the town has undergone a number of marked changes. The population dwindled from its former level of almost 20,000 to 16,500. Many prefabricated concrete structures, common in the former Warsaw Pact countries, were modernized and adapted to new demands. In addition, a few schools were closed and new hotels built. Historical downtown was completely renovated and decorated, giving it a new appeal.


a