/**                         _       _______
                           | |     |____   /
                           | |          / /
                           | |         / /
                           | |____    / /
                           |______|  /_/
**/

#include<bits/stdc++.h>
using namespace std;
void dbg_out(){
    cerr<<endl;
}
template <typename Head,typename... Tail>
void dbg_out(Head H,Tail... T){
    cerr<<' '<<H;
    dbg_out(T...);
}
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
typedef         long long ll;
typedef         long double ld;
typedef         vector<ll>vl;
typedef         deque<ll>dq;
typedef         pair<ll,ll>pl;
#define         yes {cout<<"YES"<<endl;return;}
#define         no {cout<<"NO"<<endl;return;}
#define         CR(_) {cout<<_<<endl;return;}
#define         F first
#define         S second
#define         pb push_back
#define         ppb pop_back
#define         pf push_front
#define         ppf pop_front
#define         aff(v) for(auto e:v) cout<<e<<" ";cout<<endl;
#define         all(v) v.begin(), v.end()
#define         rall(v) v.rbegin(), v.rend()
//const           ll MOD = LLONG_MAX;
//const           ll MOD = 998244353;
const           ll MOD=1000000007;
const           ld eps=1e-7;
const           double PI=acos(-1);
const           int N=2e5+5;
const           ll INF=1e18;
const           int L=log2(N)+1;

string to_bin(ll n){
    string ch="";
    while(n>0){
        char a=n%2+'0';
        ch=a+ch;
        n=n/2;
    }
    return ch;
}

int to_dec(string ch){
    int res=0;
    for(int i=ch.size()-1;i>=0;i--){
        int a=ch[i]-'0';
        int p=ch.size()-i-1;
        if(a)res+=1<<p;
    }
    return res;
}

void solve(){
    int n;cin>>n;
    int k;cin>>k;
    vector<int>v(n);
    for(int i=0;i<n;i++)cin>>v[i];
    string shit="";
    for(int i=0;i<k;i++){
        shit+='1';
    }
    for(int i=k;i<10;i++){
        shit+='0';
    }
    int ans=to_dec(shit);
    int op=0;
    vector<bool>vis(1024,0);
    vector<int>vect;vect.pb(0);
    vector<bool>done(1024);
    vis[0]=1;
    for(int i=0;i<n;i++){
        op=v[i]^op;
        if(vis[op])continue;
        for(auto j:vect){
            int cur=op^j;
            ans=max(ans,cur);

            if(done[cur])continue;
            else done[cur]=1;

            string bin=to_bin(cur);
            while(bin.size()<10)bin='0'+bin;

            int alpha=k;
            for(int f=0;f<10;f++){
                if(alpha==0)break;
                if(bin[f]=='0'){
                    bin[f]='2';alpha--;
                }
            }
            for(int f=9;f>=0;f--){
                if(alpha==0)break;
                if(bin[f]=='1'){
                    bin[f]='0';alpha--;
                }
            }
            for(int f=0;f<10;f++)if(bin[f]=='2')bin[f]='1';
            ans=max(ans,to_dec(bin));
        }
        if(!vis[op]){
            vis[op]=1;
            vect.pb(op);
        }
    }
    cout<<ans<<endl;
}
int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);
    int _=1;
    cin>>_;
    //cout<<fixed<<setprecision(6);
    while(_--)solve();
}