Instructions: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Input: Passage: Judging by the historical records, by approximately 1000 AD the predominant ethnic group over much of modern European Russia, Ukraine and Belarus was the Eastern branch of the Slavs, speaking a closely related group of dialects. The political unification of this region into Kievan Rus' in about 880, from which modern Russia, Ukraine and Belarus trace their origins, established Old East Slavic as a literary and commercial language. It was soon followed by the adoption of Christianity in 988 and the introduction of the South Slavic Old Church Slavonic as the liturgical and official language. Borrowings and calques from Byzantine Greek began to enter the Old East Slavic and spoken dialects at this time, which in their turn modified the Old Church Slavonic as well.
Output:
What group of dialects did Christians speak in 1000 AD?