Let u and v be vectors in R. Which of the following is/are true? (select all that apply) The set of all vectors which are scalar multiple of a nonzero vector u is a line through u and 0. The magnitude of a vector cv is c times the magnitude of v, where c is any scalar. The operation of vector addition is not commutative. None of the choices is correct. A column vector in R is a 1 x 2 matrix.