vectors and column spaces

question: V is the column space of a 4x2 matrix, which is column 1 is 1,2,0,1 and column 2 is 1,0,0,1. find a vector v in V such that u-v is orthogonal to V, where the vector u= 1,1,1,1 matrix.

i'm guessing its linear independent, but have no idea.