221197
His father , Muhammad ibn Yazdad al-Marwazi , had been an official in the caliphal bureaucracy , and had served as the final secretary for the caliph al-Ma ' mun prior to the latter 's death in 833 .
 person: ibn
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: ibn 
Answer:
 person: ibn