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reporter : in days of yore , an english prince , a king in waiting would be charging off to battle on a horse , just before his 21st birthday , prince william is chasing a polo ball , such of what has become of the british monarchy over time .
 prince: attacker; king: attacker
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: attack 
  Option: victim, attacker, place, target, instrument 
Text: {0} 
Answer:
 prince: attacker; king: attacker