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: Who was the head monk at Alvastra Abbey when Stephen lived there? Passage:The first Archbishop of Uppsala was Stephen, a Cistercian monk from the celebrated Alvastra Abbey. Cardinal William of Sabina came as papal legate to Sweden during the archiepiscopate of Jarler, a Dominican friar (1235–55). The legate had been commissioned, among other things, to establish cathedral chapters wherever such were lacking, and to grant them the exclusive right of electing the bishops. Another important matter which the legate had been ordered to carry out was the enforcement of the law of clerical celibacy. At a provincial synod held at Skänninge in 1248 under the presidency of the cardinal, the rules as to celibacy were made more severe. The pious and energetic Archbishop Jarler and his successor Laurentius (1257–67), a Franciscan, constantly strove to elevate the clergy and to enforce the law of celibacy. A century later Saint Bridget (d. 1373), laboured zealously for the enforcement of the same law.


a