List<Prices> List1 = new List<Prices>();
    List1.Add(new Prices { Year = 2018, Price = 1.5m });
    List1.Add(new Prices { Year = 2017, Price = 1.2m });
    List1.Add(new Prices { Year = 2016, Price = 3.5m });

    //The linq query i'm trying to build
     var data1 = List1.Select(c=> new
         {
             labels = new List<Int64> {f=> f.Year },
             series = new List<decimal> {
                 new List<decimal> { Convert.ToDecimal(c.Price) }
             }
         });


    // it's what i want to build
    var data2 = new {
      labels = new List<Int64> { 2018, 2017, 2016 },
      series = new List<decimal[]> {
               new decimal[] { 1.5m, 1.2m, 3.5m }
        }
    };

    var Json = JsonConvert.SerializeObject(data2);
    //Json => {"labels":[2018,2017,2016],"series":[[1.5,1.2,3.5]]}