Quarter Hour String Generator, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            String s = "00:00";
            
            for (int i = 1; i < 96; i++) {
                int h = i / 4;
                int m = i % 4;
                switch (m)
                  {
                      case 1:
                          m = 15;
                          break;
                      case 2:
                          m = 30;
                          break;
                      case 3:
                          m = 45;
                          break;
                      default:
                          break;
                  }
                s += string.Format(",{0:00}:{1:00}", h,m);
            }
            
            Console.WriteLine(s);
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,12 sec, absolute running time: 0,08 sec, cpu time: 0,06 sec, average memory usage: 10 Mb, average nr of threads: 3