$4.$ Assume there are two processes $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash )$ that share semaphores $\backslash ($ r $\backslash )$ and $\backslash ($ s $\backslash ).$ They are initialized as $\backslash ($ r$=0,$ s$=1\backslash ),$ and processes $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash )$ execute the following code.

Decide whether the following explanation is true or false and explain why. $[3$ points$]$

$(1)$ Operation$1()$ cannot be executed until Operation$3()$ is completed.

$(2)$ Operations$1()$ and Operation$5()$ cannot be executed simultaneously.

$(3)$ The system may experience a deadlock.