Suppose u · v = 0. Which vectors could represent u and v?

a) u = ⟨3, 4⟩ and v = ⟨4, –3⟩
b) u = ⟨3, 4⟩ and v = ⟨–4, –3⟩
c) u = ⟨–3, 4⟩ and v = ⟨4, –3⟩
d) u = ⟨–3, –4⟩ and v = ⟨–4, –3⟩