The correct option is B |u|×(w−v)
(u+v)×(u−w),being cross product of two vectors. hence make sense.
||u||is scalar and (w-v) is vector. Cross product of scalar and vector does not make sense.
||u||(v×w) is scalar multiple of vector. hence make sense.
u+(v−w)is addition and subtraction of vectors.Hence make sense.