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 old was Robert Guiscard when he defeated the papal troops of Pope Leo IX? Passage:San Severo lies on the Daunia, and various Neolithic settlements have been detected. In the early Middle Ages, the area was not inhabited or defined. Between the Lombards and the Byzantine ages, the Benedictine monastery at Cassino was established, and with it, the cult of the apostle of Saint Severinus of Noricum. San Severo was founded in the 11th century around a small church built by the Benedictine monks from Montecassino. It rapidly developed as a trade town. In 1053, it was the scene of the historical victory of Robert Guiscard over the papal troops under Pope Leo IX (see Battle of Civitate). In the eleventh century, San Severo was the route of the Via Sacra Langobardorum and a primitive church arose dedicated to Saint Severino, from which continued an influx of pilgrims to Monte Sant'Angelo and movement of people and goods. The town was therefore called Castellum Sancti Severini ("Fortified Town of San Severo").


a