Notice the following code $.$ Assume the MyRunnable$()$ is a class extending the Runnable interface. What's the purpose of the highlighted code? public static void main$($String$[]$ args$)\{$ Thread t$1=$ new Thread$($new MyRunnable$(),"$t$1")$; Thread t$2=$ new Thread$($new MyRunnable$(),"$t$2")$; Thread t$3=$ new Thread$($new MyRunnable$(),"$t$3")$; t$1.$start$()$; t$2.$start$()$; try $\{$ t$1.$join$()$; t$2.$join$()$; $\}$ catch $($InterruptedException e$)\{$ e$.$printStackTrace$()$; $\}$ t$3.$start$()$; $\}.$ Forces program to wait until threads t$1$ & t$2$ are complete before starting t$3.$ Forces program to wait until thread t$1$ is complete before starting t$2.$ Threads t$1$ and t$2$ are potentially running concurrently Thread t$2$ isn$$t started until thread t$1$ is complete