basic syntax error

I have a problem. In my script error Assets/Scripts/NewBehaviourScript.js(27,19): BCE0044: expecting :, found ‘=’.This is Script:
var b_IsShowMenu : boolean;
var b_IsShowGame : boolean;
var b_IsShowOptions : boolean;
var b_IsMusicOn : boolean;

function Start () {

b_IsShowMenu = true;
b_IsShowOptions = false;
b_IsShowGame = false;
b_IsMusicOn = true;


}

function Update () {

}

function OnGUI() {
 if(b_IsShowMenu) 
 {
  GUILayout.BeginArea(new Rect(Screen.Width/2-50, Screen.Height/2, 100, 100)); 
  GUILayout.BeginVertical();
   if(GUILayout.Button("Play")); 
   {
     b_IsShowMenu = false;
     b_IsShowGame = true;
     b_IsMusicOn = false;
  } 
  if(GUILayout.Button("Options"));
  {
  b_IsShowMenu = false;
  b_IsShowOptions = true;
  }
  if(GUILayout.Button(GUILayout.Button("Quit"));
  {
  Application.Quit();
  }
  GUILayout.EndVertical();
  GUILayout.EndArea();

You have a lot of if statements with a final semicolon, like

if(GUILayout.Button("Options"));

Remove all those “;” and it should work.