In which of the following situations is Defendant most likely to be guilty of first-degree murder?
Angered over having been struck by Sam, Defendant buys rat poison and puts it into Sam's coffee. Sam drinks the coffee and dies as a result. 
Intending to injure Fred, Defendant lies in wait and, as Fred comes by, strikes him with a broom handle. As a result of the blow, Fred dies. 
Defendant, highly intoxicated, discovers a revolver on a table. He picks it up, points it at Alice, and pulls the trigger. The gun discharges, and Alice is killed. 
Immediately after being insulted by Robert, Defendant takes a knife and stabs and kills Robert. 