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A group calling itself XMR Squad has spent all last week launching DDoS attacks against German businesses and then contacting the same companies to inform them they had to pay € 250 ( $ 275 ) for " testing their DDoS protection systems . "
 ( ransom: pay,  they: victim, € 250: price, $ 275: price, launching DDoS attacks: attack pattern, German businesses: victim, the same companies: victim, last week: time, XMR Squad: attacker) 
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: pay,  they: victim, € 250: price, $ 275: price, launching DDoS attacks: attack pattern, German businesses: victim, the same companies: victim, last week: time, XMR Squad: attacker) 