A Splunk instance has crashed, but no crash log was generated.

Searching for closed_txn=0 in this search filters results to situations where Splunk was started, but not stopped. This means that the transaction was not completed, and Splunk crashed before it could finish the pipelines. The closed_txn field is added by the transaction command, and it indicates whether the transaction was closed by an event that matches the endswith condition1. A value of 0 means that the transaction was not closed, and a value of 1 means that the transaction was closed1. Therefore, option D is the correct answer, and options A, B, and C are incorrect.

1: transaction command overview