Give the poles and zeros of the causal filter represented by the impulse response: h(n) = 2 (u(n) - u(n-3)). poles at z = j, zeros at z = -j O poles at z = 4, zeros at z =-4 Onone is correct O poles at z = 0, zeros at z= (-1tj*sqrt(3))/2 O poles at z = 0, zeros at z = (-1j*sqrt(2))/2