#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
void *wmem;
char memarr[96000000];
template <class S, class T>
inline S max_L(S a, T b) {
  return a >= b ? a : b;
}
template <class T>
inline void walloc1d(T **arr, int x, void **mem = &wmem) {
  static int skip[16] = {0, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
  (*mem) = (void *)(((char *)(*mem)) + skip[((unsigned long long)(*mem)) & 15]);
  (*arr) = (T *)(*mem);
  (*mem) = ((*arr) + x);
}
template <class T1>
void sortA_L(int N, T1 a[], void *mem = wmem) {
  sort(a, a + N);
}
inline int my_getchar() {
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if (s == e && e == 1048576) {
    e = fread(buf, 1, 1048576, stdin);
    s = 0;
  }
  if (s == e) {
    return EOF;
  }
  return buf[s++];
}
inline void rd(int &x) {
  int k;
  int m = 0;
  x = 0;
  for (;;) {
    k = my_getchar();
    if (k == '-') {
      m = 1;
      break;
    }
    if ('0' <= k && k <= '9') {
      x = k - '0';
      break;
    }
  }
  for (;;) {
    k = my_getchar();
    if (k < '0' || k > '9') {
      break;
    }
    x = x * 10 + k - '0';
  }
  if (m) {
    x = -x;
  }
}
inline void rd(long long &x) {
  int k;
  int m = 0;
  x = 0;
  for (;;) {
    k = my_getchar();
    if (k == '-') {
      m = 1;
      break;
    }
    if ('0' <= k && k <= '9') {
      x = k - '0';
      break;
    }
  }
  for (;;) {
    k = my_getchar();
    if (k < '0' || k > '9') {
      break;
    }
    x = x * 10 + k - '0';
  }
  if (m) {
    x = -x;
  }
}
inline int rd_int(void) {
  int x;
  rd(x);
  return x;
}
struct MY_WRITER {
  char buf[1048576];
  int s;
  int e;
  MY_WRITER() {
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER() {
    if (s) {
      fwrite(buf, 1, s, stdout);
    }
  }
};
MY_WRITER MY_WRITER_VAR;
void my_putchar(int a) {
  if (MY_WRITER_VAR.s == MY_WRITER_VAR.e) {
    fwrite(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a) { my_putchar(a); }
inline void wt_L(int x) {
  int s = 0;
  int m = 0;
  char f[10];
  if (x < 0) {
    m = 1;
    x = -x;
  }
  while (x) {
    f[s++] = x % 10;
    x /= 10;
  }
  if (!s) {
    f[s++] = 0;
  }
  if (m) {
    my_putchar('-');
  }
  while (s--) {
    my_putchar(f[s] + '0');
  }
}
template <class S, class T>
inline S chmax(S &a, T b) {
  if (a < b) {
    a = b;
  }
  return a;
}
int N;
long long K;
int X[200000];
int Y[200000];
int dp[200000 + 1];
int dp1[200000 + 1];
int dp2[200000 + 1];
int main() {
  int Lj4PdHRW;
  wmem = memarr;
  int KL2GvlyY = rd_int();
  for (Lj4PdHRW = (0); Lj4PdHRW < (KL2GvlyY); Lj4PdHRW++) {
    int loop;
    int i;
    int k;
    int res = 0;
    rd(N);
    rd(K);
    {
      int cTE1_r3A;
      for (cTE1_r3A = (0); cTE1_r3A < (N); cTE1_r3A++) {
        rd(X[cTE1_r3A]);
      }
    }
    {
      int xr20shxY;
      for (xr20shxY = (0); xr20shxY < (N); xr20shxY++) {
        rd(Y[xr20shxY]);
      }
    }
    sortA_L(N, X);
    for (loop = (0); loop < (2); loop++) {
      dp[0] = 0;
      k = 0;
      for (i = (0); i < (N); i++) {
        while (X[k] < X[i] - K) {
          k++;
        }
        dp[i + 1] = max_L(dp[i], i - k + 1);
      }
      for (i = (0); i < (N); i++) {
        X[i] = 1000000000 - X[i];
      }
      reverse(X, X + N);
      if (loop == 0) {
        for (i = (0); i < (N + 1); i++) {
          dp1[i] = dp[i];
        }
      }
      if (loop == 1) {
        for (i = (0); i < (N + 1); i++) {
          dp2[i] = dp[i];
        }
      }
    }
    for (i = (0); i < (N + 1); i++) {
      chmax(res, dp1[i] + dp2[N - i]);
    }
    wt_L(res);
    wt_L('\n');
  }
  return 0;
}
