I want to know the answer to the following question:
What pact contained many Russian-speaking countries?
All the background I'm provided with is that "According to the Eurobarometer 2005 survey, though, fluency in Russian remains fairly high (20–40%) in some countries, in particular those where the people speak a Slavic language and thereby have an edge in learning Russian (namely, Poland, Czech Republic, Slovakia, and Bulgaria).". Is that enough to answer the question?
Answer: no