a client who is NPO for surgery later in the morning
a client complaining of nausea after eating breakfast
a client recently complaining of shortness of breath
Number 4 is correct.
Shortness of breath is a medical emergency and can be life-threatening, so this client should be seen first. A client with a UTI and fever may be uncomfortable, but is not in any immediate danger. The client who is NPO awaiting surgery is stable and can wait to be seen. The client with nausea can be seen after attending to the client who is short of breath.