MVC - Fix the following error - The type or namespace name 'SelectListItem' could not be found (are you missing a using directive or an assembly reference?)

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Error while executing the following code:
        public IEnumerable<SelectListItem> Months
        {
            get
            {
                return DateTimeFormatInfo
                       .InvariantInfo
                       .MonthNames
                       .Select((monthName, index) => new SelectListItem
                       {
                           Value = (index + 1).ToString(),
                           Text = monthName
                       });
            }
        }

To fix it add the following using:
using System.Globalization;