package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
)

type IntHeap []int64

func (h IntHeap) Len() int           { return len(h) }
func (h IntHeap) Less(i, j int) bool { return h[i] < h[j] }
func (h IntHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *IntHeap) Push(x interface{}) {
	*h = append(*h, x.(int64))
}

func (h *IntHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

func readInt(in *bufio.Reader) int64 {
	var n int64
	var c byte
	var err error
	var sign int64 = 1
	for {
		c, err = in.ReadByte()
		if err != nil {
			return 0
		}
		if c == '-' {
			sign = -1
			continue
		}
		if c >= '0' && c <= '9' {
			n = int64(c - '0')
			break
		}
	}
	for {
		c, err = in.ReadByte()
		if err != nil || c < '0' || c > '9' {
			break
		}
		n = n*10 + int64(c-'0')
	}
	return n * sign
}

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	t := int(readInt(in))
	for i := 0; i < t; i++ {
		n := int(readInt(in))
		m := int(readInt(in))
		d := readInt(in)

		h := &IntHeap{}
		var sum int64 = 0
		var maxVal int64 = 0

		for j := 1; j <= n; j++ {
			a := readInt(in)
			if a > 0 {
				heap.Push(h, a)
				sum += a
				if h.Len() > m {
					sum -= heap.Pop(h).(int64)
				}
			}
			ans := sum - d*int64(j)
			if ans > maxVal {
				maxVal = ans
			}
		}
		fmt.Fprintln(out, maxVal)
	}
}