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And ransomware attacks have claimed a number of recent victims , especially healthcare systems , including MedStar Health , which suffered a major attack affecting 10 hospitals and more than 250 outpatient centers in March 2016 .
 ( ransom: a major attack,  hospitals: victim, outpatient centers: attacker, March 2016: time) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: phishing, data breach, ransom, discover vulnerability, patch vulnerability, Arguments type: vulnerable system, capabilities, vulnerability, number of victim, issues addressed, compromised data, damage amount, common vulnerabilities and exposures, victim, patch number, number of data, tool, discoverer, time, purpose, place, payment method, releaser, vulnerable system version, attacker, supported platform, patch, price, vulnerable system owner, trusted entity, attack pattern. 
Text: {0} 
Answer:
 ( ransom: a major attack,  hospitals: victim, outpatient centers: attacker, March 2016: time) 