Definition: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it, i.e., the proper nouns in the passage. Your job is to determine whether information from more than one term is needed to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: What did Ahmad Sanjar build the wall out of? Passage:The Abbasid-era geographers report that the town was the centre of a flourishing agricultural region, with a number of dependent suburbs such as Qasr-i Ahnaf. According to al-Muqaddasi, who wrote in ca. 980, the locals were kin of the people of Gharjistan, and the town was a dependency of the rulers, or Shirs, of Gharjistan. A section of the Harbiyya district of the Round city of Baghdad was named Marwrūdiyya () after the people from this city. The town continued to flourish under the Seljuk Empire, when the Seljuk ruler Ahmad Sanjar built the city a new wall, some 5,000 paces in circumference. The town and the surrounding area suffered during the constant conflicts between the Khwarazmshahs and the Ghurids in the late 12th century, and a battle was fought there between the Ghurid ruler Ghiyath al-Din Muhammad (r. 1163–1202) and his Khwarazmian rival Sultan Shah (r. 1172–1193) in 1190. Although the town appears to have escaped the destruction of Marw al-Shahijan by the Mongols, it fell into ruin under the Timurids and was largely abandoned.


a