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: How long had the Great Slav Rising been occurring when Otto III appointed Eckard I, Margrave of Meissen to succeed Margrave Rikdag? Passage:In 985 Otto III appointed him to succeed Margrave Rikdag in Meissen, following severe Saxon setbacks against the Slavic Lutici tribes during the Great Slav Rising. Eckard remained a vital support for the king and his mother Empress Theophanu. His military responsibilities consisted primarily of securing the Milceni lands as well as the containment of the neighbouring Polish and Bohemia duchies. Duke Boleslaus II of Bohemia had allied with Duke Henry and had taken the occasion to occupy the Albrechtsburg residence, he nevertheless had to withdraw by 987, after Eckard's forces had prevailed. According to the chronicles of Thietmar of Merseburg, he was later elected Duke of Thuringia by the magnates of the region, an event which has been taken as evidence of the principle of tribal ducal election. 


b