The correct option is B can never be zero
Let the vectors lie in X−Y plane.
We can write the vectors as →A=Ax^x+Ay^y and →B=Bx^x+By^y
Vector C lies outside the plane, so →C=Cx^x+Cy^y+Cz^z
We get →A+→B+→C =(Ax+Bx+Cx)^x+(Ay+By+Cy)^y+Cz^z
We can have some values such that the value of (Ax+Bx+Cx) can be zero and (Ay+By+Cy) can be zero. But Cz can not be zero as it is given that →C lies outside the plane.
⟹ →A+→B+→C≠0
So, option B is correct.