Given the task definition and input, reply with output. In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: What was the name of the Holy Roman Emporer who preceded the Emporer who granted his follower Franko land in 945? Passage:In 945, Bosenbach had its first documentary mention when Otto I, Holy Roman Emperor, granted his faithful follower Franko a few landholds. To better describe where these landholds lay, both Reichenbach and Bosenbach were named. Either Franko or his heirs yielded these lands shortly after 945 to Saint Maximin's Abbey in Trier. Until about 1100, Bosenbach was listed time and again as being among the monastery's holdings. Territorially, Bosenbach belonged to the Imperial Domain (Reichsland) around Kaiserslautern and about 1130, it came to be held as a Palatine fief by the Counts of Veldenz. About 1282, the Amt of Bosenbach (Bosenbach, Niederstaufenbach and Friedelhausen) was held in common ownership by the Counts of Veldenz and the Waldgraves. Later, in the 14th and 15th centuries, the common ownership had ended and it was owned by the Waldgraves and Rhinegraves (one group). In 1595, through territorial trade, the Amt found its way back into the Duchy of Palatinate-Zweibrucken. From the years 1514, 1537 and 1578 come three Weistumer dealing with Bosenbach (a Weistum cognate with English wisdom was a legal pronouncement issued by men learned in law in the Middle Ages and early modern times; Weistumer is the plural).
Links: a. English language b. Middle Ages c. Trier d. Otto I, Holy Roman Emperor
d