Exam CPP topic 1 question 69 discussion

Which method added to class B at the marked spot will allow the code below to compile? Choose all possible solutions.
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
class B { int val;
public:
B(int v):val(v){}
int getV() const {return val;}
/* Insert Code Here */
};
ostream & operator <<(ostream & out, const B & v) { out<<v.getV(); return out;} template<class T>struct Out { ostream & out;
Out(ostream & o): out(o){}
void operator() (const T & val ) { out<<val<<" "; } }; int main() { int t[]={8, 10, 5, 1, 4, 6, 2, 7, 9, 3}; vector<B> v1(t, t+10); sort(v1.begin(), v1.end(), greater<B>()); for_each(v1.begin(), v1.end(), Out<B>(cout));cout<<endl; return 0;
}