2423
All morning , the Kurds have been trying to advance , and that was the shell going off .
 attack: going off
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: declare bankruptcy, transfer ownership, marry, die, phone write, arrest jail, convict, sue, transfer money, end organization, start organization, end position, merge organization, start position, transport, charge indict, elect, attack, injure, born, extradite, release parole, sentence, demonstrate, meet, trial hearing, divorce, nominate, fine, appeal, pardon, execute, acquit 
Text: {0} 
Answer:
 attack: going off