Which of these is a scalar multiple of ⟨2,4⟩\langle 2, 4 \rangle⟨2,4⟩?
⟨1,2⟩\langle 1, 2 \rangle⟨1,2⟩
⟨4,8⟩\langle 4, 8 \rangle⟨4,8⟩
⟨2,0⟩\langle 2, 0 \rangle⟨2,0⟩
⟨−1,−2⟩\langle -1, -2 \rangle⟨−1,−2⟩