From the following, select all statements that are true.

A. If x is not in a subspace W, then x-projW(x) is not zero.
B. In a QR factorization, say A=QR (when A has linearly independent columns), the columns of Q form an orthonormal basis for the column space of A.
C. If W=Span{v1,v2,v3}, and if {v1,v2,v3} is an orthogonal set in W, then {v1,v2,v3} is an orthonormal basis for W.
D. None of the above.