How to group items by index? C# LINQ

Question

Suppose I have

var input = new int[] { 0, 1, 2, 3, 4, 5 };

How do I get them grouped into pairs?

var output = new int[][] {         


        

Answer 1

var input = new int[] { 0, 1, 2, 3, 4, 5 };
int i = 0;
var output = input.GroupBy(item => i++ / 2);