Second Highest Distinct Salary with LINQ

int[] salaries = { 90000, 75000, 75000, 60000 };

Console.WriteLine(NthHighest(salaries, 2)?.ToString() ?? "none");    // 75000
Console.WriteLine(NthHighest(salaries, 5)?.ToString() ?? "none");    // none
Console.WriteLine(NthHighest(new[] { 50000 }, 2)?.ToString() ?? "none");   // none

// Distinct first, so people sharing the top salary do not count as different ranks.
// Returns null when there are fewer than n distinct values.
static int? NthHighest(IEnumerable<int> values, int n) =>
    values.Distinct()
          .OrderByDescending(v => v)
          .Skip(n - 1)
          .Select(v => (int?)v)
          .FirstOrDefault();