Detailed Instructions: 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.
Q: Question: How old was John of Damascus when the Islamic Caliphate overtook the land of his home? Passage:The earliest surviving written criticisms of Islam are to be found in the writings of Christians who came under the early dominion of the Islamic Caliphate. One such Christian was John of Damascus (c. 676749 AD), who was familiar with Islam and Arabic. The second chapter of his book, The Fount of Wisdom, titled "Concerning Heresies", presents a series of discussions between Christians and Muslims. John claimed an Arian monk (whom he did not know was Bahira) influenced Muhammad and viewed the Islamic doctrines as nothing more than a hodgepodge culled from the Bible. Writing on Islam's claim of Abrahamic ancestry, John explained that the Arabs were called "Saracens" (Greek , Sarakenoi) because they were "empty" (, kenos, in Greek) "of Sarah". They were called "Hagarenes" because they were "the descendants of the slave-girl Hagar".

A:
a