context: We took a bus ride to Tulum to visit the Mayan ruins . Our tour guide , Manuel , was very knowledgable about the ruins and the Mayan culture and lectured on the interesting points as we drove along . We stopped on the way to buy some souvenirs from the locals .
question: Why is Manuel so knowledgeable ?
reference: He has studied Mayan history
candidate: Manuel is interested in the Mayan history.