I would say that both options are legal since the sequencing of messages
over multiple associations is not defined in the DICOM standard.
In particular, even if the SCP selects option A, the same kind of
race condition could cause the SCU to receive the N-EVENT-REPORT-RSP
before the N-ACTION-RSP, i.e. effectively "see" option B.
I would, therefore, argue that failure to correctly handle this
situation would be a failure of the SCU. If the SCU supports incoming
associations, then it also needs to be able to handle possible