The Printer Event

$1$ P$1$ requests and is allocated the printer R$1.$

$2$ P$1$ releases the printer R$1.$

$3$ P$2$ requests and is allocated the disk drive R$2.$

$4$ P$2$ releases the disk R$2.$

$5$ P$3$ requests and is allocated the plotter R$3.$

$6$ P$3$ releases the plotter R$3.$

Assume that the events in the accompanying narrative take place. Which of the following statements is true?