public static void Main()
DateTime date = DateTime.Now;
int quarterNumber = (DateTime.Now.Month - 1) / 3 + 1;
DateTime firstDayOfQuarter = new DateTime(date.Year, (quarterNumber - 1) * 3 + 1, 1);
DateTime lastMonthOfQuarter = firstDayOfQuarter.AddMonths(2);
Console.WriteLine(firstDayOfQuarter);
Console.WriteLine(lastMonthOfQuarter);