open System

​

let printOut = function 

                | "" -> "-1"

                | s -> s

// Apply filters & prepare output

let filter l k =

    l

    |> Seq.countBy (id)

    |> Seq.filter( fun (n, count) -> count >= k)

    |> Seq.map ( fst >> string)

    |> String.concat " "

    |> printOut

​

let readArray() = Console.ReadLine().Split [|' '|] |> Array.map int

​

[<EntryPoint>]

let main argv = 

    let t = Console.ReadLine() |> int

    Array.init t 

        (fun _ -> 

            let [|n; k|] = readArray()

            let arr = readArray()

            k, arr)

    |> Array.map (fun (k, arr) -> filter arr k)

    |> Array.map (printfn "%s")

    |> ignore

    0