Answer:A.) Quietly and carefully evaluate the situation and keep your emotions under control. Be as unhurried as you can.
Explanation: What I consider to be most appropriate in such scenario is to be calm and calculated due to certain reasons, such as, The presence of the police shows that, if an imminent attack had been spotted, the cops at the scene would have reacted, the context says the scene is safe, and the man on the counter was repeatedly singing a birthday song. With all these, careful evaluation without hurry is required, there is no need to rush or be emotional. it could just be a surprise birthday call, who knows.