You can leave out the statements in a switch structure.
a.
switch
b.
if
c.
case
d.
break

break

Explanation:

Break is the statement in the programming which is used to terminate the loop or case in the switch structure.

Break immediately terminate or move program control to next statement outside the loop or switch structure.

For example:

for(int i=0;i<4;i++)

{

   print("hello world");

   break;

}

when the program execution reach to the break statement. The loop structure terminate and program control goes to next of for loop.

similarly for switch case,

switch(int number)

{

case 1:

         print("hello");

         break;

}

when the program execution reach to the break statement. it terminate the switch structure.

none because it's so obvious