Please help! C++ problem!

Choose the best solution (Analyze ALL the possible answers before choosing):

Write a bool function, areSame, to accept two vectors of ints and return true if the two vectors contain the same values in every cell. The vectors are the same size. Efficiency counts!

a)

bool areSame(const vector &V1, const vector &V2) { bool OK = true; int i=0; for(int i=0; i < V1.size());i++) { if(V1[i] != V2[i]) OK = false; } return OK; } b)bool areSame(const vector &V1, const vector &V2) { bool OK = false; int i=0; while(OK && i < V1.size()) { if(V1[i] == V2[i]) i++; else OK = true; } return OK; } c)bool areSame(const vector &V1, const vector &V2) { bool OK = true; int i=0; while(OK && i < V1.size()) { if(V1[i] == V2[i]) i++; else OK = false; } return OK; } d)bool areSame(const vector &V1, const vector &V2) { bool OK; int i=0; for(int i=0; i < V1.size());i++) { if(V1[i] != V2[i]) OK = false; } else OK = false; return OK; }