Which of the following is the correct way to define and initialise an array of 4 integers?

1. int[] a = {25, 30, 40, 5};

2. int[] a;
   a = new int[3];
   a[0] = 25;
   a[1] = 30;
   a[2] = 40;
   a[3] = 5;

3. int[] a;
   a = new int{25, 30, 40, 5};

4. int[] a;
   a = new int[4]{25, 30, 40, 5};

5. int[] a;
   a = new int[4];
   a[0] = 25;
   a[1] = 30;
   a[2] = 40;
   a[3] = 5;